[clang] [clang] Fix pretty-printing assume_aligned attributes (PR #67331)

[Erich Keane via cfe-commits]

erichkeane wrote:

Also, it appears that the clang-format bot dislikes this commit (but frustratingly won't tell us why?), so perhaps run `git clang-format against all the commits here`

https://github.com/llvm/llvm-project/pull/67331