[clang] [clang-format] Add a new style for the clang-format source code (PR #69814)

[via cfe-commits]

mydeveloperday wrote:

> Where is the documentation for the value? CLion reports `clang-format` option as an error by the reason. No doc, no schema rule.

Personally, I'm not a fan of CLion enough to care! especially following JetBrains slating of clang-format:  (thanks for doing that at a massive public C++ forum without contacting us), their content even questionable as to its accuracy. 

https://www.youtube.com/watch?v=NnQraMtpvws
https://blog.jetbrains.com/clion/2023/12/a-clangformat-story-and-the-third-clion-nova-update/

Maybe they can try contributing rather than complaining.

https://github.com/llvm/llvm-project/pull/69814