[clang] [clang-format] add BinPackLongBracedLists style option (PR #112482)

[Gedare Bloom via cfe-commits]

gedare wrote:

> I think it should be merges with `BinPackArguments` to get an enum
> 
> * Never
> * TwentyOrAbove (name is debatable)
> * Always
> * (Leave?)

Currently the 20 item limit is only enforced on C++ initializer lists. Making it part of the `BinPackArguments` means it has to apply to any bin packing situation, so the scope of the style option increases. I'm not convinced it is worth doing.

https://github.com/llvm/llvm-project/pull/112482