[clang-tools-extra] Add refactoring tool to convert between ternary (?:) expressions and equivalent if/else statements (PR #166822)

[via cfe-commits]

https://github.com/EugeneZelenko commented:

Please add documentation and Release Notes entry.

I don't think that this check belongs to `modernize`, most likely to `readability`, since it's code style issue.

https://github.com/llvm/llvm-project/pull/166822