[clang] Carving out -Wformat warning about scoped enums into a subwarning (PR #88595)

[via cfe-commits]

pirama-arumuga-nainar wrote:

> Please mention that this fixes #81647 in the patch summary so that the issue is automatically closed.
> 
> You should also add a release note so that users know about the change (and link to the issue being closed).

This is also pending.  The rest of the changes LGTM.

https://github.com/llvm/llvm-project/pull/88595