[clang] [RFC] Initial implementation of P2719 (PR #113510)

[Aaron Ballman via cfe-commits]

https://github.com/AaronBallman commented:

Thank you for working on this!

The changes should come with release notes in clang/docs/ReleaseNotes.rst so users know about the new functionality.

Unless this is slated for inclusion in C++26, it should probably also come with user-facing documentation in the language extensions file.

https://github.com/llvm/llvm-project/pull/113510