minor fixes

Author: AlbertoMontalesi

ebook/07_iterables-and-looping.md

@@ -129,7 +129,7 @@ for (const index in fruits){
 // gnam gnam
 ```
 
-Since `for in` will return the value and not the value itself, we need to access with the syntax `fruits[index]`.
+Since `for in` will return the index and not the value itself, we need to access with the syntax `fruits[index]`.
 
 As you can see, the `for in` loop returned the value of the property `eat` which we've added after initialization of the variable `fruits`.
 On the other hand, the `for of` loop only returned the values that were in the array when we initialized it.

ebook/13_promises.md

@@ -1,6 +1,13 @@
 # Chapter 13: Promises
 
 `JavaScript` work **synchronously** which means that each block of code will be executed after the previous one.
+
+```javascript
+const data = fetch('your-api-url-goes-here');
+console.log('Finished');
+console.log(data);
+```
+
 In the example above, we're using `fetch` to retrieve data from a url (in this example we're only pretending to be doing so).
 
 In case of synchronous code we would expect the subsequent line to be called only after the `fetch` has been completed. But in reality, what's going to happen is that `fetch` will be called, and straight away the subsequent two `console.log` will also be called, resulting in the last one `console.log(data)` to return `undefined`.