[clang] [clang] Implement instantiation context note for checking template parameters (PR #126088)

[Matheus Izvekov via cfe-commits]

mizvekov wrote:

It's not exactly the same patch, had more changes on top, but the meat with the expected impact was the same.

Anyway, thanks for the revert, will investigate.

https://github.com/llvm/llvm-project/pull/126088