[clang-tools-extra] clangd: Extend reference search with constructor calls through forwarding (PR #169742)

[Nathan Ridge via cfe-commits]

HighCommander4 wrote:

[Here's](https://github.com/clangd/clangd/issues/1104#issuecomment-2833972488) a tidbit from a previous investigation that may be relevant. It suggests that the background indexer does skip parsing function bodies in some situations (basically, in files that haven't changed since the last time they were indexed), though it's not clear to me yet how that would be applicable here.

https://github.com/llvm/llvm-project/pull/169742