[clang] [Clang] Warn when an explicit alignment is weakened by other directives (PR #198417)

[Aaron Ballman via cfe-commits]

https://github.com/AaronBallman commented:

Thank you for working on this! Please be sure to also add a release note to `clang/docs/ReleaseNotes.rst` so users know about the improvements.

https://github.com/llvm/llvm-project/pull/198417