Summary: Ref T10967. `differential.createcomment` is a frozen API method which has been obsoleted by `differential.revision.edit`. It is the only remaining way to apply an "accept", "reject", or "resign" action using the old "ACTION" code. Instead of using the old code, sneakly apply a new type of transaction in these cases instead. Then, remove all the remaining old code for this stuff on the write pathways. Test Plan: - Used "differential.createcomment" to accept, reject, and resign from a revision. - Grepped for all removed ACTION_X constants, found them only in rendering code. Reviewers: chad Reviewed By: chad Maniphest Tasks: T10967 Differential Revision: https://secure.phabricator.com/D17513