[clang] [clang] improve diagnostics for enums (PR #204682)

[Corentin Jabot via cfe-commits]

cor3ntin wrote:

> Do we need to opt out of this in [CGDebugInfo::getPrintingPolicy](https://github.com/llvm/llvm-project/blob/f05a649741f248e3809a6d0e7b5a8daf7bed74a8/clang/lib/CodeGen/CGDebugInfo.cpp#L445) as well?

Probably yes - I'd rather be conservative

https://github.com/llvm/llvm-project/pull/204682