chore: Disable whitespace trimming in MD files and fix MD009 (mdn#12309)

Author: nschonni

.editorconfig

@@ -10,3 +10,6 @@ end_of_line = lf
 charset = utf-8
 trim_trailing_whitespace = true
 insert_final_newline = true
+
+[*.md]
+trim_trailing_whitespace = false

files/en-us/mozilla/add-ons/webextensions/build_a_cross_browser_extension/index.md

@@ -9,9 +9,9 @@ tags:
 ---
 {{AddonSidebar()}}
 
-> **Note:** This article discusses building cross-browser extensions for manifest v2. At the time of writing (December 2021), manifest v3 is being introduced by the major browser vendors. Manifest v3 is likely to change the way cross-browser extension development is undertaken. However, work on Manifest v3 is not complete. The major browser vendors are collaborating (with community members) to ease the development of a cross-browser extension in the [W3C WebExtensions Community Group](https://github.com/w3c/webextensions). 
+> **Note:** This article discusses building cross-browser extensions for manifest v2. At the time of writing (December 2021), manifest v3 is being introduced by the major browser vendors. Manifest v3 is likely to change the way cross-browser extension development is undertaken. However, work on Manifest v3 is not complete. The major browser vendors are collaborating (with community members) to ease the development of a cross-browser extension in the [W3C WebExtensions Community Group](https://github.com/w3c/webextensions).
 
-The introduction of the browser extensions API created a uniform landscape for the development of browser extensions. However, there are differences in the API implementations and the scope of coverage among the browsers that use the extensions API (the major ones being Chrome, Edge, Firefox, Opera, and Safari). 
+The introduction of the browser extensions API created a uniform landscape for the development of browser extensions. However, there are differences in the API implementations and the scope of coverage among the browsers that use the extensions API (the major ones being Chrome, Edge, Firefox, Opera, and Safari).
 
 Maximizing the reach of your browser extension means developing it for at least two browsers, possibly more. This article looks at six of the main challenges faced when creating a cross-browser extension and suggests how to address these challenges.
 

files/en-us/mozilla/firefox/experimental_features/index.md

@@ -105,7 +105,7 @@ The {{domxref("HTMLElement")}} property {{DOMxRef("HTMLElement.inert")}} is a {{
 
 ### Layout for input type="search"
 
-Layout for `input type="search"` has been updated. This causes a search field to have a clear icon once someone starts typing in it, to match other browser implementations. (See {{bug(558594)}} for more details)
+Layout for `input type="search"` has been updated. This causes a search field to have a clear icon once someone starts typing in it, to match other browser implementations. (See {{bug(558594)}} for more details)
 
 <table>
   <thead>
@@ -555,7 +555,7 @@ The [`@layer`](en-US/docs/Web/CSS/@layer) rule declares a cascade layer, which a
 ### Property: hyphenate-character
 
 The {{cssxref("hyphenate-character")}} property can be used to set a string that is used instead of a hyphen character (`-`) at the end of a hyphenation line break.
-It can also be used to specify that the character is selected to be appropriate for the language conventions of the affected content. 
+It can also be used to specify that the character is selected to be appropriate for the language conventions of the affected content.
 (See {{bug(1746187)}} for more details.)
 
 <table>
@@ -1147,7 +1147,7 @@ The [Clipboard.read()](/en-US/docs/Web/API/Clipboard/read) method of the {{domxr
 
 #### HTML Sanitizer API
 
-The {{domxref('HTML Sanitizer API')}} allow developers to take untrusted strings of HTML and sanitize them for safe insertion into a document’s DOM. Default elements within each configuration property (those to be sanitized) are still under consideration. Due to this the config parameter has not been implemented (see {{domxref('Sanitizer.sanitizer()', 'the constructor')}}) for more information. See {{bug('1673309')}} for more details.
+The {{domxref('HTML Sanitizer API')}} allow developers to take untrusted strings of HTML and sanitize them for safe insertion into a document’s DOM. Default elements within each configuration property (those to be sanitized) are still under consideration. Due to this the config parameter has not been implemented (see {{domxref('Sanitizer.sanitizer()', 'the constructor')}}) for more information. See {{bug('1673309')}} for more details.
 
 <table>
   <thead>
@@ -1878,7 +1878,7 @@ The Network Monitor displays information for [server-sent](/en-US/docs/Web/API/S
 
 ### CSS browser compatibility tooltips
 
-The CSS Rules View can display browser compatibility tooltips next to any CSS properties that have known issues. For more information see: [Examine and edit HTML > Browser Compat Warnings](/en-US/docs/Tools/Page_Inspector/How_to/Examine_and_edit_HTML#browser_compat_warnings).
+The CSS Rules View can display browser compatibility tooltips next to any CSS properties that have known issues. For more information see: [Examine and edit HTML > Browser Compat Warnings](/en-US/docs/Tools/Page_Inspector/How_to/Examine_and_edit_HTML#browser_compat_warnings).
 
 <table>
   <thead>

files/en-us/mozilla/firefox/releases/18/index.md

@@ -32,14 +32,14 @@ Firefox 18 was released on January 8, 2013. This article lists key changes that
 - {{domxref("BlobBuilder", "MozBlobBuilder")}} is removed. Developers need to use {{domxref("Blob")}} constructor for creating a `Blob` object. ({{bug("744907")}})
 - The {{event("visibilitychange")}} event and the [Page Visibility API](/en-US/docs/Web/API/Page_Visibility_API) has been unprefixed ({{bug("812086")}}).
 - {{domxref("TextDecoder")}} and {{domxref("TextEncoder")}} have been added. Note that the implementation and spec of these evolved and have been changed in Firefox 19 ({{bug("764234")}}).
-- ` HTMLMediaElement.src` has been separate in two properties: the standard `src` property, dealing with {{domxref("DOMString")}}, and the prefixed `mozSrcObject` property, dealing with [media streams](/en-US/docs/Web/API/Media_Streams_API) ({{bug("792665")}}).
+- `HTMLMediaElement.src` has been separate in two properties: the standard `src` property, dealing with {{domxref("DOMString")}}, and the prefixed `mozSrcObject` property, dealing with [media streams](/en-US/docs/Web/API/Media_Streams_API) ({{bug("792665")}}).
 - Support for [transferable objects.](/en-US/docs/Web/API/Web_Workers_API/Using_web_workers#passing_data_by_transferring_.c2.a0ownership_%28transferable_objects%29)
 - The {{domxref("Screen.lockOrientation()")}} method now supports an `Array` of {{domxref("DOMString")}} as argument ({{bug("784549")}}.
 
 ### JavaScript
 
 - Harmony's (ECMAScript 2015) [Direct Proxies](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy) have been landed ({{bug("703537")}}). Warning: the implementation contains a couple of known bugs, missing features and misalignments with the current state of the spec. Do not rely on it for production code.
-- The ECMAScript 2015 `contains()` method is now implemented on strings. This is unfortunately not compatible with Mootools 1.2, which expects different behavior from `contains()` on strings but does not ensure it. Newer versions of Mootools fix this issue; sites should upgrade their Mootools version to something newer than 1.2.
+- The ECMAScript 2015 `contains()` method is now implemented on strings. This is unfortunately not compatible with Mootools 1.2, which expects different behavior from `contains()` on strings but does not ensure it. Newer versions of Mootools fix this issue; sites should upgrade their Mootools version to something newer than 1.2.
 
 ### WebGL
 

files/en-us/web/accessibility/aria/aria_techniques/index.md

@@ -143,7 +143,7 @@ The techniques below describe each composite role as well as their required and
 
 - [`aria-dropeffect`](/en-US/docs/Web/Accessibility/ARIA/Attributes/aria-dropeffect) {{deprecated_inline}}
 - [`aria-grabbed`](/en-US/docs/Web/Accessibility/ARIA/Attributes/aria-grabbed) {{deprecated_inline}}
- 
+
 ### Relationship attributes
 
 - [`aria-activedescendant`](/en-US/docs/Web/Accessibility/ARIA/Attributes/aria-activedescendant)

files/en-us/web/accessibility/aria/attributes/aria-describedby/index.md

@@ -14,7 +14,7 @@ The global `aria-describedby` attribute identifies the element (or elements) tha
 
 ## Description
 
-The `aria-describedby` attribute lists the {{HTMLattrxref('id')}}s of the elements that describe the object. It is used to establish a relationship between widgets or groups and the text that describes them. 
+The `aria-describedby` attribute lists the {{HTMLattrxref('id')}}s of the elements that describe the object. It is used to establish a relationship between widgets or groups and the text that describes them.
 
 The `aria-describedby` attribute is not limited to form controls. It can also be used to associate static text with widgets, groups of elements, regions that have a heading, definitions, and more. The `aria-describedby` attribute can be used with semantic HTML elements and with elements that have an ARIA [`role`](/en-US/docs/Web/Accessibility/ARIA/Roles/).
 
@@ -39,7 +39,7 @@ The `aria-describedby` property is appropriate when the associated content conta
 ## Values
 
 - ID reference list
-  - : The `id` or space-separated list of elements IDs that describe the current element. 
+  - : The `id` or space-separated list of elements IDs that describe the current element.
 
 ## Associated roles
 

files/en-us/web/accessibility/aria/attributes/aria-labelledby/index.md

@@ -10,13 +10,13 @@ tags:
   - Reference
 ---
 
-The `aria-labelledby` attribute identifies the element (or elements) that labels the element it is applied to. 
+The `aria-labelledby` attribute identifies the element (or elements) that labels the element it is applied to.
 
 ## Description
 
-The `aria-labelledby` property enables authors to reference other elements on the page to define an accessible name. This is useful when using elements that don't have native support for associating elements to provide an accessible name. 
+The `aria-labelledby` property enables authors to reference other elements on the page to define an accessible name. This is useful when using elements that don't have native support for associating elements to provide an accessible name.
 
-Some elements get their [accessible name](/en-US/docs/Glossary/Accessible_Name) from their inner content. For example, the accessible name for a {{HTMLElement('button')}}, {{HTMLElement('a')}}, or {{HTMLElement('td')}} comes from the text between the opening and closing tags. Other elements, such as form {{HTMLElement('textarea')}}, {{HTMLElement('fieldset')}}, and {{HTMLElement('table')}} get their accessible name from the content of associated elements; for these elements, the accessible name comes from the {{HTMLElement('label')}} with a `for` attribute, {{HTMLElement('legend')}}, and {{HTMLElement('caption')}} respectively. 
+Some elements get their [accessible name](/en-US/docs/Glossary/Accessible_Name) from their inner content. For example, the accessible name for a {{HTMLElement('button')}}, {{HTMLElement('a')}}, or {{HTMLElement('td')}} comes from the text between the opening and closing tags. Other elements, such as form {{HTMLElement('textarea')}}, {{HTMLElement('fieldset')}}, and {{HTMLElement('table')}} get their accessible name from the content of associated elements; for these elements, the accessible name comes from the {{HTMLElement('label')}} with a `for` attribute, {{HTMLElement('legend')}}, and {{HTMLElement('caption')}} respectively.
 
 All interactive elements must have an accessible name. `aria-labelledby` can be used to reference another element to define its accessible name, when an element's accessible name needs to use content from elsewhere in the DOM.
 
@@ -58,8 +58,8 @@ Fortunately, the HTML {{HTMLElement('input')}} with `type="checkbox"` works with
    <span id="color">Yellow</span>
    ```
 
-In this example, that accessible name is "Yellow". 
-   
+   In this example, that accessible name is "Yellow".
+
 2. The `aria-labelledby` property takes as value an id reference list, which means you can combine more than one element into a single accessible name. You can include the {{htmlattrxref('id')}} of the element itself to reference its own content.
 
    ```html
@@ -69,18 +69,18 @@ In this example, that accessible name is "Yellow".
    </p>
    ```
 
-In this example, the accessible name is "read more 13 ARIA attributes you need to know".
-   
+    In this example, the accessible name is "read more 13 ARIA attributes you need to know".
+
 3. The `aria-labelledby` property value order matters. When more than one element is referenced by `aria-labelledby`, the content from each referenced element is combined in the order that they are referenced in the `aria-labelledby` value. Had we written `aria-labelledby="attr rm13">`, the accessible name would have been "13 ARIA attributes you need to know read more".
-       
+
 4. The `aria-labelledby` property ignores repeated `id`s in its value. If an element is referenced more than one time, only the first reference is processed. `aria-labelledby="attr attr rm13 rm13">` is treated as `aria-labelledby="attr rm13">`
 
 5. The `aria-labelledby` property value can include content from elements that aren't even visible. While you should provide assistive technology users with the same content and all other users, you can include content from elements with the HTML {{htmlattrxref('hidden')}} attribute, CSS [`display: none`](/en-US/docs/Web/CSS/display), and CSS [`visibility: hidden`](/en-US/docs/Web/CSS/visibility) in the calculated name string.
-   
+
 6. The `aria-labelledby` property incorporates the value of input elements. If the value references an `<input>`, the current value of the form control is included in the calculated name string, changing if the value is updated.
-   
+
 7. The `aria-labelledby` property cannot be chained. If an element with `aria-labelledby` references another element that also has `aria-labelledby`, the `aria-labelledby` attribute on the referenced element is ignored.
-   
+
 > **Warning:** Because calculating the name of an element with `aria-labelledby` can be complex and reference hidden content, testing with assistive technologies to ensure the expected name is presented to users is very important.
 
 ## Values
@@ -96,7 +96,7 @@ The `aria-labelledby` attribute is **NOT** supported in [`code`](/en-US/docs/Web
 
 ## Specifications
 
-| Specification | Status | 
+| Specification | Status |
 | ------------- | ------  |
 | {{SpecName("ARIA","#aria-labelledby","ARIA: aria-labelledby Attribute")}}  | {{Spec2('ARIA')}} |