Empty pull request list item in issue 422

[kraai]

The tenth pull request list item in issue 422 is empty. The original text is

* [add `[T]::as_simd(_mut)`](https://github.com/rust-lang/rust/pull/91479)

I think that the Markdown formatter interprets the item body as a reference link definition for add `T.

[ericseppanen]

This formatting glitch is really weird. I tried to figure out what's happening:

• It's the right-bracket ] that is the problem
• but only when it's followed by a colon ]:
• and there is an open-parenthesis too (

I can't find any explanation of why this doesn't work; the python commonmark module handles this correctly, so I can only conclude that it's a bug in the Markdown library.

edit: filed a bug.

[ericseppanen]

As a really dirty hack, if you put a unicode zero-width space character in between the ] and :, then it no longer triggers the bug.

[ericseppanen]

Here's a slightly less hacky way to work around the Markdown bug: just add something else to the list item. For example, adding an html space   at the end of the affected line will stop the bug from happening.

[ericseppanen]

Fixed by #2784.