[clang] [PATCH 1/6] [clang] Improve nested name specifier AST representation (PR #147835)

[Matheus Izvekov via cfe-commits]

mizvekov wrote:

I have further split up this patch series, now the changes related to the NNS representation are moved last in the patch series: https://github.com/llvm/llvm-project/pull/149748

I have also moved some of the trivial changes into yet another patch: https://github.com/llvm/llvm-project/pull/149747

As a result, this and the other patches in the series are smaller.
Let me know if that's enough, or if you would rather I keep splitting further.

Otherwise, I have addressed all pending reviews, and this is ready for another round.

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