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

[Gedare Bloom via cfe-commits]

gedare wrote:

I would also be ok to have a style option to make the existing 20-item limit optional (but enabled by default). That might be a little more maintainable than allowing arbitrary limits to be used. There will be bugs if/when people use this option with small values for the limit, as it will interact weirdly with both the braced list initializer formatting rules, and also with the `AvoidBinPacking` logic of the continuation indenter.

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