Emit unconfigured code diagnostics for enum variants and struct/union fields

[unexge]

Fixes https://github.com/rust-lang/rust-analyzer/issues/12664

[bors]

:umbrella: The latest upstream changes (presumably #13288) made this pull request unmergeable. Please resolve the merge conflicts.

[Veykril]

Thanks! @bors r+

[bors]

:pushpin: Commit 7e5e5177b60c7986d6d8b776b112219d99d23969 has been approved by Veykril

It is now in the queue for this repository.

[bors]

:hourglass: Testing commit 7e5e5177b60c7986d6d8b776b112219d99d23969 with merge b01cdd89d581b2580396b846784d92c1cc128e05...

[bors]

:sunny: Test successful - checks-actions Approved by: Veykril Pushing b01cdd89d581b2580396b846784d92c1cc128e05 to master...