Rename `PhutilRemarkupRule` subclasses

Summary: Ref T5655. Depends on D9993.

Test Plan: See D9993.

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: epriestley, Korvin

Maniphest Tasks: T5655

Differential Revision: https://secure.phabricator.com/D9994