Reorder remarkup block rules for consistency with PhabricatorMarkupEngine

Summary: I got consistent failures on the remarkup tests. This resolves that issue by bringing the order in line with the order used in PhabricatorMarkupEngine::newMarkupEngine

Test Plan: No more failures when running arc unit src/markup/engine/PhutilRemarkupEngine.php

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D15859