Mark answers as page objects in Ponder

Summary:
Fixes T4306. We should clear notifications about a question and its answers when viewing a question page.

(Eventually we might have an answer detail page and send the notification there, and then only clear there, but this cleans things up for now.)

Test Plan: Loaded question page, verified answers appeared as page objects.

Reviewers: chad, btrahan

Reviewed By: chad

CC: aran

Maniphest Tasks: T4306

Differential Revision: https://secure.phabricator.com/D7928

src/applications/ponder/controller/PonderQuestionViewController.php

@@ -69,7 +69,9 @@ final class PonderQuestionViewController extends PonderController {
       array(
         'device' => true,
         'title' => 'Q'.$question->getID().' '.$question->getTitle(),
-        'pageObjects' => array($question->getPHID()),
+        'pageObjects' => array_merge(
+          array($question->getPHID()),
+          mpull($question->getAnswers(), 'getPHID')),
       ));
   }