Add 'json' as a value for Sec-Fetch-Dest (#42160)

Add 'json' as a value for sec-fetch-dest

Author: bakkot

files/en-us/web/http/reference/headers/sec-fetch-dest/index.md

@@ -44,6 +44,7 @@ Sec-Fetch-Dest: font
 Sec-Fetch-Dest: frame
 Sec-Fetch-Dest: iframe
 Sec-Fetch-Dest: image
+Sec-Fetch-Dest: json
 Sec-Fetch-Dest: manifest
 Sec-Fetch-Dest: object
 Sec-Fetch-Dest: paintworklet
@@ -86,6 +87,8 @@ Servers should ignore this header if it contains any other value.
   - : The destination is an iframe. This might originate from an HTML {{HTMLElement("iframe")}} tag.
 - `image`
   - : The destination is an image. This might originate from an HTML {{HTMLElement("img")}}, SVG {{SVGElement("image")}}, CSS {{cssxref("background-image")}}, CSS {{cssxref("cursor")}}, CSS {{cssxref("list-style-image")}}, etc.
+- `json`
+  - : The destination is JSON. This might originate from [importing a module from JavaScript with the `type: "json"` attribute](/en-US/docs/Web/JavaScript/Reference/Statements/import/with#importing_json_modules_with_the_type_attribute).
 - `manifest`
   - : The destination is a manifest. This might originate from an HTML [\<link rel=manifest>](/en-US/docs/Web/HTML/Reference/Attributes/rel/manifest).
 - `object`