[clang] [PAC] Add support for __ptrauth type qualifier (PR #100830)

[Aaron Ballman via cfe-commits]

https://github.com/AaronBallman commented:

Thank you for this! Please be sure to add a release note to `clang/docs/ReleaseNotes.rst` as we get closer to finalizing on the PR so users know about the feature.

I started a pass over the PR but ran out of time before I could get to Parse and Sema, so there's more to come at some point.

https://github.com/llvm/llvm-project/pull/100830