[clang] [clang-format] Add option AllowShortRecordOnASingleLine (PR #154580)

[Björn Schäpers via cfe-commits]

https://github.com/HazardyKnusperkeks commented:

I'm too unfamiliar with the whole merging part, I can't give an approval.

https://github.com/llvm/llvm-project/pull/154580