[clang-tools-extra] [clangd] Place lambda return type hints after exception specifications (PR #219829)

[via cfe-commits]

Machillka wrote:

Thank you for reviewing! While re-checking this fix, I've found tow cases that are not coverd yet

- C++23 lambda without an explicit param-list, for instance,  `[] noexcept {}`
- deduced-return functions like `auto foo() noexcept`

They both still anchor the return type hint before the exception specification.

I'm going to update this PR with regression tests and fix to those cases, then request another review.

https://github.com/llvm/llvm-project/pull/219829