[clang] [clang][Sema] Deprecate `global`/`unknown` in `lifetime_capture_by` (PR #196635)

[Gábor Horváth via cfe-commits]

https://github.com/Xazax-hun commented:

The code changes look good to me. Could you add a lifetime analysis test where multiple  `lifetime_capture_by` attributes are present on the same parameter making sure we take all of them into account? I also wonder if we want to add a restriction that only one `lifetime_capture_by` spelling is allowed. E.g., I cannot have `lifetime_capture_by(a, b) lifetime_capture_by_(c, d)`, but I can have `lifetime_capture_by(a, b) lifetime_capture_by_this`. So every spelling can appear at most once?


https://github.com/llvm/llvm-project/pull/196635