[clang] Support variable empty lines between include categories (PR #183960)

[Paul Hoad via cfe-commits]

phoad107185 wrote:

I'm kind of with the others, This seems to just increase complexity for what feel like an extreme corner case, is there are public style you are trying to achieve with this? can we understand what problem you are trying to solve?

https://github.com/llvm/llvm-project/pull/183960