[clang-tools-extra] Update clang tidy Contributing guide (PR #106672)

[Aaron Ballman via cfe-commits]

AaronBallman wrote:

There is no workaround on Windows currently; the issue is that tab autocompletion is handled via https://github.com/llvm/llvm-project/blob/0797c184c636889f2897746dc71390ae28005c7c/llvm/lib/LineEditor/LineEditor.cpp#L212 and that's not available on Windows; we don't have any fallback code for it.

There is https://sourceforge.net/projects/mingweditline/ (no idea how well it would work in practice), so perhaps there's a different library we could consume on Windows to provide the functionality.

https://github.com/llvm/llvm-project/pull/106672