Convert AphrontDialogView to safe HTML

Summary:
Done by searching for `AphrontDialogView` and then `appendChild()`.

Also added some `pht()`.

Test Plan: None.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4882

src/applications/help/controller/PhabricatorHelpKeyboardShortcutController.php

@@ -37,10 +37,10 @@ final class PhabricatorHelpKeyboardShortcutController
         ));
     }
 
-    $table =
-      '<table class="keyboard-shortcut-help">'.
-        implode('', $rows).
-      '</table>';
+    $table = phutil_tag(
+      'table',
+      array('class' => 'keyboard-shortcut-help'),
+      $rows);
 
     $dialog = id(new AphrontDialogView())
       ->setUser($user)