[clang] [clang-tools-extra] [clangd] Fixed signature help for static call operator (C++23) (PR #199192)

[via cfe-commits]

Ippo47 wrote:

> Could you please add tests with lambdas with `static` specifier?
> 
> ```c++
>    []() static {};
> //      ^^^^^^
> ```

i will add it 

https://github.com/llvm/llvm-project/pull/199192