r? requests should ignore zero-width spaces

[tgross35]

There are some cases where it looks like Rustbot doesn't pick up review requests:

• fix: #128855 Ensure Guard's drop method is removed at opt-level=s for `… rust#128862
• Port rustc perf cmp command rust#128868
• Improve Ord docs rust#129003

@ehuss noticed on zulip that these comments contain a zero-width space. I am not sure where this would be coming from - maybe GitHub adds them when you autocomplete an @ name - but rustbot should probably work around this.

[apiraino]

What the GH comment contains

$ hexdump -C test.txt 
00000000  72 e2 80 8b 3f 20 40 73  63 6f 74 74 6d 63 6d 0a  |r...? @scottmcm.|
00000010

What I expect to the text to be

$ hexdump -C test1.txt 
00000000  72 3f 20 40 73 63 6f 74  74 6d 63 6d 0a           |r? @scottmcm.|

So yes that U+200B is added somehow. Tried adding a comment to a PR letting GH autocomplete my username and it looks fine.

Seems unlikely, but I wonder if these weird whitespaces are added by the user client when opening the PR.

[tgross35]

I have no clue, one of those is mine and I didn't do anything out of the ordinary. Spurious GH bug?