[clang] Qualify non-dependent types of a class template with its declaration (PR #67566)

[Luca Di sera via cfe-commits]

diseraluca wrote:

Run clang-format on the patch.

I made a bit of a mess as I haven't used the PR model in a very long time. Hopefully this is correct.

https://github.com/llvm/llvm-project/pull/67566