edited special layout

The special layout was changed, including "cite this page" link.

Author: JoramSoch

_layouts/special.html

@@ -22,6 +22,7 @@ <h1 class="post-title">Special: {{ page.title }}</h1>
   <!-- "edit this page" -->
   <div style="text-align:right">
     <small><a href="https://github.com/StatProofBook/StatProofBook.github.io/blob/master/S/{{ page.shortcut }}.md">view/edit this page</a></small>
+	<small><a href="/citations/">cite this page</a></small>
   </div>
 
 </article>