[clang] [C++20] [Modules] Don't check redeclaration for TagUseKind::Referencekind declaration (PR #194546)

[Chuanqi Xu via cfe-commits]

ChuanqiXu9 wrote:

> LGTM, but can you at least add a comment explaining loose threads from the discussion here? I think it would be worth exploring to simply not add a redeclaration in this case.

Done

https://github.com/llvm/llvm-project/pull/194546