[clang] [Clang] Separate implicit int conversion on negation sign to new diagnostic group (PR #139429)

[Yutong Zhu via cfe-commits]

YutongZhuu wrote:

> LGTM! Failing docs build in precommit CI appears to be unrelated

Hi, I don't have commit access, so I might need you to merge it for me :)

https://github.com/llvm/llvm-project/pull/139429