pick: update commit message hashes like other rewrite commands Maybe it would be better to use `evolvecmd._relocate()`, which does this already, but I don't know what subtle behavior changes that would trigger. Also, there are other commands (like `metaedit`) that use `rewriteutil.rewrite` instead, and so don't refresh their hashes either. We probably need a better way to track all of this, but I'm not sure how.