[clang] [Clang] [Sema] Handle placeholders in '.*' expressions (PR #83103)

[via cfe-commits]

Sirraide wrote:

> Thank you for the fix! Please be sure to add a release note to `clang/docs/ReleaseNotes.rst` so users know about the fix (and be sure to mention the issue # in the release note).

Ah yes, I keep forgetting about that

https://github.com/llvm/llvm-project/pull/83103