Use attribute parser for #[non_exhaustive] attribute check

[obeis]

Updates #153101

r? @JonathanBrouwer

[rustbot]

Some changes occurred in compiler/rustc_attr_ir

cc @jdonszelmann, @JonathanBrouwer

Some changes occurred in compiler/rustc_passes/src/check_attr.rs

cc @jdonszelmann, @JonathanBrouwer

Some changes occurred to diagnostic attributes.

cc @mejrs

Some changes occurred in compiler/rustc_attr_parsing

cc @jdonszelmann, @JonathanBrouwer

[mejrs]

I'm not sure about this change. We'd like to have more of these checks in attribute parsing but we also don't want to make Target more complicated. I think this one is too much "makes Target complicated".

[JonathanBrouwer]

Indeed, this information also feels too specific to add to the Target type for me.

[JonathanBrouwer]

@rustbot author

[rustbot]

Reminder, once the PR becomes ready for a review, use @rustbot ready.

[rustbot]

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.