Update the async/await docs in the "Learn web development" module

[ghost]

Request type

• [ ] Please close this issue, I accidentally submitted it without adding any details
• [ ] New documentation
• [x] Correction or update

Details

The issue concerns the following page: https://developer.mozilla.org/en-US/docs/Learn/JavaScript/Asynchronous/Async_await

In the "The downsides of async/await" section, a timeTest code from fast-async-await.html is provided as an example where we create and await promises separately and speed up the execution:

However, the solution used here can lead to unhandled promise rejection errors, as mentioned in another reference doc about async functions (see the "Examples" section):

Additional, more detailed explanation about the downsides of this approach can also be found on StackOverflow.

As a fix, a similar note highlighting the issues can be provided on the page, or perhaps the example can be reworked to use Promise.all.

[chrisdavidmills]

Issue moved to mdn/content #1445 via ZenHub