[clang] [llvm] Convert clang-format to Opt and add multicall support (PR #201730)

[via llvm-commits]

mydeveloperday wrote:

My concern is we rarely add new options but I kind of feel like if this was landed then when we did we'd need to unpick and relearn how to do it? I don't think this is broken, I'm inclined not to fix it unless there is some significant benefit. Minimum is there a GitHub issue with a problem statement?

https://github.com/llvm/llvm-project/pull/201730