[clang] [BitInt] Expose a _BitInt literal suffix in C++ (PR #86586)

[Aaron Ballman via cfe-commits]

https://github.com/AaronBallman commented:

The changes LGTM but I'd like to give Corentin and Tom a chance to weigh in as lexer code owners (you may need to be patient as they were both in WG21 meetings last week and are currently on vacation, so it may be later next week before we hear back).

https://github.com/llvm/llvm-project/pull/86586