[clang] [Windows] Add git-clang-format wrapper bat file (PR #69228)

[Björn Schäpers via cfe-commits]

HazardyKnusperkeks wrote:

I have no real opinion on this matter, as I don't use that program/script. But when it helps the windows users, why not? I also see no harm.

https://github.com/llvm/llvm-project/pull/69228