[clang-tools-extra] [clangd] Add config option to allow detection of unused system headers (PR #87208)

[Nathan Ridge via cfe-commits]

HighCommander4 wrote:

Since the patch is approved, and as far as I can tell there aren't any comments remaining to be addressed, I will go ahead and merge this.

https://github.com/llvm/llvm-project/pull/87208