Add link to phabricator help on 500 error.
<div id="main-content">
<h2>Internal server error</h2>
<p>Something went wrong.</p>
- <p>Please email us about this error at <a href="mailto:wikipedialibrary@wikimedia.org?Subject=Wikipedia%20Library%20Server%20Error">wikipedialibrary@wikimedia.org</a> or report it to us on <a href="https://phabricator.wikimedia.org/maniphest/task/edit/form/1/?projectPHIDs=Library-Card-Platform&title=Wikipedia%20Library%20Server%20Error">Phabricator</a> (login required).</p>
+ <p>
+ Please email us about this error at <a href="mailto:wikipedialibrary@wikimedia.org?Subject=Wikipedia%20Library%20Server%20Error">wikipedialibrary@wikimedia.org</a> or report it to us on <a href="https://phabricator.wikimedia.org/maniphest/task/edit/form/1/?projectPHIDs=Library-Card-Platform&title=Wikipedia%20Library%20Server%20Error">Phabricator</a>
+ (<a href="https://www.mediawiki.org/wiki/Phabricator/Help">?</a>).
+ </p>
<img src="500-dog.jpeg" class="img-responsive">
<!-- photo via https://unsplash.com/photos/NhRJJwzGRXQ under a CC0 license -->
</div>
