[clang-tools-extra] [clangd] Allow "move function body out-of-line" in non-header files (PR #69704)

[Christian Kandeler via cfe-commits]

ckandeler wrote:

I'm going to merge this without explicit format approval based on the following:
  - There was a general LGTM.
  - I addressed the remaining issues.
  - There was no further feedback for more than half a year.

https://github.com/llvm/llvm-project/pull/69704