[clang] [clang] [Serialization] No transitive change for MacroID and PreprocessedEntityID (PR #166346)

[Jan Svoboda via cfe-commits]

https://github.com/jansvoboda11 commented:

This is great, thanks for working on this. I left mostly small style suggestions, but I'd really appreciate stronger typing of `MacroID` and friend.

https://github.com/llvm/llvm-project/pull/166346