Add suffix to feed title

This is already done in the base template for HTML.

_templates/atom.xml

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <feed xmlns="http://www.w3.org/2005/Atom">
-  <title>{{ title }}</title>
+  <title>{{ title }} - Look What the Shoggoth Dragged In</title>
   <link href="{{ permalink }}" rel="self" />
   <link href="{{ base_href }}" />
   <id>{{ permalink }}</id>