[clang] [llvm] Reland "[DebugMetadata][DwarfDebug] Support function-local types in lexical block scopes (4/7)" (PR #165032)

[Adrian Prantl via llvm-commits]

https://github.com/adrian-prantl commented:

The description of the the problem in the PR makes sense to me, but it would help future maintainers to also explain this better in the comments for the new APIs in the header files.

https://github.com/llvm/llvm-project/pull/165032