[clang-tools-extra] [clangd] Add inlay hints for default function arguments (PR #95712)

[Tor Shepherd via cfe-commits]

torshepherd wrote:

Hmm another case to consider:

![image](https://github.com/user-attachments/assets/193c9570-0e6b-47cd-8d8c-0279e727eac2)

In this case the argument is unnamed. I think for this I should just insert `/* unused */` or `/* unnamed */` ?

https://github.com/llvm/llvm-project/pull/95712