Make Pholio description behave as a remarkup field (e.g., subscribe mentioned users)

Summary: Ref T12732. This is pre-existing but fix it since I caught it while banging around.

Test Plan: {F4967442}

Reviewers: chad, amckinley

Reviewed By: chad

Maniphest Tasks: T12732

Differential Revision: https://secure.phabricator.com/D17970

src/applications/pholio/xaction/PholioMockDescriptionTransaction.php

@@ -44,4 +44,14 @@ final class PholioMockDescriptionTransaction
       ->setNewText($this->getNewValue());
   }
 
+  public function newRemarkupChanges() {
+    $changes = array();
+
+    $changes[] = $this->newRemarkupChange()
+      ->setOldValue($this->getOldValue())
+      ->setNewValue($this->getNewValue());
+
+    return $changes;
+  }
+
 }