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

[Björn Schäpers via cfe-commits]

HazardyKnusperkeks 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.

Buggy would be no break? That would be what I expect from `None`. :) So +1 from me.

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