Mark 'closed' as translatable

Summary:
This is to allow conservative people to bring back the old manners.

NOTE: It doesn't mark all occurrences but I think that's good enough. We will eventually mark them all.

Test Plan: Translated 'closed', displayed closed revision.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin, asukhachev

Maniphest Tasks: T1139

Differential Revision: https://secure.phabricator.com/D2760

src/applications/differential/controller/DifferentialRevisionListController.php

@@ -379,7 +379,7 @@ final class DifferentialRevisionListController extends DifferentialController {
             array(
               'all'       => 'All',
               'open'      => 'Open',
-              'closed'    => 'Closed',
+              'closed'    => pht('Closed'),
               'abandoned' => 'Abandoned',
             ));
       case 'order':