For "request changes", allow specifying the requesting persona

We have a Herald rule to add the “db-migrations” project as a group reviewer on all differential revision that touch DB migrations.

The problem:

  • I often quickly review the DB migration component of the revision and and accept as the “db-migrations” entity.
  • Later, I may do “request changes” for some other component of the revision.
  • Unfortunately, this also marks the “db-migrations” entity as having requested changes, which puts the review back in the other “db-migrations” reviewers’ feeds, even though there’s nothing for them to do.

When accepting a revision, Phabricator gives me the ability to specify which entity I’m accepting as. I’d like to be able to specify the entity when doing “request changes” as well.