[clang] Thread Safety Analysis: Warn when using negative reentrant capability (PR #141599)

[Aaron Ballman via cfe-commits]

https://github.com/AaronBallman commented:

Thanks for the new diagnostic! I think you should also add a release note to `clang/docs/ReleaseNotes.rst` so users know about the new diagnostic group.

https://github.com/llvm/llvm-project/pull/141599