[clang] [clang-tools-extra] [clang] Improve nested name specifier AST representation (PR #147835)

[Andrey Ali Khan Bolshakov via cfe-commits]

bolshakov-a wrote:

Ah, sorry. I tested on IWYU and get confused because it transforms a declaration to the definition later.

https://github.com/llvm/llvm-project/pull/147835