[llvm-branch-commits] [PM] Move PassInfoMixin to detail namespace (PR #218198)

[Alexis Engelke via llvm-branch-commits]

https://github.com/aengelke approved this pull request.

LGTM. (Would be nice to get rid of name() at some point, though, because that's somewhat expensive to instantiate.)

https://github.com/llvm/llvm-project/pull/218198