[clang] [Sema] Fix assertion crash on section conflict with a non-identifier decl (PR #200873)

[Corentin Jabot via cfe-commits]

https://github.com/cor3ntin commented:

This change needs a release note.
Please add an entry to `clang/docs/ReleaseNotes.rst` in the section the most adapted to the change, and referencing any Github issue this change fixes. Thanks!

LGTM otherwise

https://github.com/llvm/llvm-project/pull/200873