[C23] Add __TYPE_FMTB__ and __TYPE_FMTb__ predefined macros (#82361)

This adds predefined formatting macros in C23 mode for printing unsigned
integers in binary format (e.g, UINT_FAST64_FMTB). These are used to
implement the PRIb (et al) macros in inttypes.h

Fixes https://github.com/llvm/llvm-project/issues/81896

(Was previously reviewed in
[82037](https://github.com/llvm/llvm-project/pull/82037), this is fixing
some failures found post-commit.)