[clang] [Clang] Implement C++26’s P2893R3 ‘Variadic friends’ (PR #101448)

[Vlad Serebrennikov via cfe-commits]

Endilll wrote:

> the date changed. weird! the resolution did not

I think it did: https://github.com/cplusplus/CWG/commit/4492036f0958d140ca14fc49ebb2a3a13f75c28c


https://github.com/llvm/llvm-project/pull/101448