try jobs=`<backtick_quoted>` regressed

[jieyouxu]

@bors2 try jobs=`x86_64-gnu-nopt`

previously worked, but now is not recognized: rust-lang/rust#142504 (comment).

I wonder if this is an unintended side-effect of #300 (I did not anticipate that to change this try job handling). cc @Kobzol

[jieyouxu]

Update: it looks like the PR description form still works, i.e.

try-job: `*-nopt`

is still correctly recognized.

[Kobzol]

Yeah I'm pretty sure that this regressed because of the Markdown parsing. We're kind of wanting conflicting behavior here; ignoring Markdown, but also using inline Markdown to avoid GH rendering part of the bors command as Markdown 😆

[Kobzol]

"please run `@bors try`" (command should be ignored)
and
@bors foo=`bar` (command argument shouldn't be ignored)

isn't all that different, and to detect the difference, I'd probably somehow have to intermingle command parsing and Markdown "pre-parsing", which sounds quite complicated.

I would just say "don't use backticks in bors command arguments". The backticks are just a hack, and I think it's fine if we only make them work for PR descriptions, but not the try command.

[jieyouxu]

Yeah, I think that's reasonable, otherwise the parsing gets really nasty.