[clang] [clang] Add clang::preferred_type attribute for bitfields (PR #69104)

[Vlad Serebrennikov via cfe-commits]

Endilll wrote:

> but I also see "you got what you asked for!" as being a reasonable defense to that.

That's my thinking indeed, and the reason why I opposed to Aaron's proposal to implicitly mark 1-bit bit-fields as `preferred_type(bool)`.

https://github.com/llvm/llvm-project/pull/69104