[clang] Add check in SemaChecking for multiple unsequenced volatile accesses (PR #180955)

[Aaron Ballman via cfe-commits]

https://github.com/AaronBallman commented:

Thank you for working on this! You should also add a release note to `clang/docs/ReleaseNotes.rst` so users know about the improvement.

https://github.com/llvm/llvm-project/pull/180955