[clang-tools-extra] issue-63565: community requested small QoL fix for more configurabili… (PR #108005)

[Nathan Ridge via cfe-commits]

HighCommander4 wrote:

> Thanks for the input, a followup question is: Which one takes precedence? Does the `--function-arg-placeholders` argument take precedence over `.clangd` config!? Or the other way around!?

`.clangd` should take precedence because it's the a more specific setting (command line arguments apply to the whole clangd process, `.clangd` files are scoped to a directory).

If you are handling the flag in `FlagsConfigProvider` as suggested, this will be the resulting behaviour will no further logic needed.

https://github.com/llvm/llvm-project/pull/108005