[clang] [clang] Finish implementation of P0522 (PR #96023)

[via cfe-commits]

cor3ntin wrote:

My concern here is that there is an ongoing lively discussion in CWG. And while I think most solutions considered will end up being isomorphic in outcome, I don't know that we want to go experimenting too much before the dust settles a bit (there is wild variation between implementations both pre and post P0522)

https://github.com/llvm/llvm-project/pull/96023