[clang] [clang][AST][NFC] Add '[[fallthrough]]' to cases fall through (PR #85921)

[Aaron Ballman via cfe-commits]

AaronBallman wrote:

> So in this case, I suppose, I’ll leave it to someone more familiar w/ codegen than me to approve/reject this pr for good.

I think in this case we should remove the comment, but maybe @rjmccall or @efriedma-quic feel differently? We could also update the comment to say something along the lines of "intentionally falling through because EmitAsmStmt knows how to handle both GCC and MSVC assembly statements."



https://github.com/llvm/llvm-project/pull/85921