[polly] [clang] [clang-format] Add AllowShortType option for AlwaysBreakAfterReturnType. (PR #78011)

[via cfe-commits]

rmarker wrote:

> > @mydeveloperday @HazardyKnusperkeks @rymiel this patch fixes a very old bug and will cause behavior changes whether the default is changed to the new `AllowShortType` or left at `None`. Which way should we go?
> 
> Now I'm leaning toward keeping the existing (buggy) behavior of `None` and using the new `AllowShortType` to allow wrapping after short return types.

Yeah, it is a tricky trade-off.
The addition of `AllowShortType`, does alleviate the buggy behaviour and addresses the issue.

I can undo the fix for determining what types are short, if you think that is the way to go after the seeing the results.
I assume that this would also include changing the `LLVMStyle.AlwaysBreakAfterReturnType` back to `None`?

https://github.com/llvm/llvm-project/pull/78011