Remove subscribe icons

Summary: Used more logical icons for subscribe, auto, and delete instead of the mail icons. Fixes T3329

Test Plan: Tested subscribing and unsubscribing in Maniphest.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Maniphest Tasks: T3329

Differential Revision: https://secure.phabricator.com/D6151

src/applications/uiexample/examples/PHUIDocumentExample.php

@@ -45,7 +45,7 @@ final class PHUIDocumentExample extends PhabricatorUIExample {
     $action5 = id(new PHUIListItemView())
       ->setName('Subscribe')
       ->setHref('#')
-      ->setIcon('subscribe-add')
+      ->setIcon('check')
       ->setType(PHUIListItemView::TYPE_LINK);
 
     $divider = id(new PHUIListItemView)