comment permalinks in xml feeds are now valid URIs

previously, comment permalinks in xml feeds were missing the scheme and
authority segments (protocol and hostname). this caused problems with
feed readers and other programs that expected to encounter a valid URI.

r2/r2/templates/comment.xml

@@ -22,6 +22,7 @@
 
 <%!
    from r2.lib.filters import safemarkdown
+   from r2.lib.template_helpers import add_sr
 %>
 
 
@@ -32,12 +33,14 @@
   else:
     author = thing.author.name
     body = thing.body
+
+  permalink = add_sr(thing.permalink, force_hostname = True)
 %>
 
 <item>
-  <guid isPermaLink="true">${thing.permalink}</guid>
+  <guid isPermaLink="true">${permalink}</guid>
   <title>${author} ${_("on")} ${thing.link.title}</title>
-  <link>${thing.permalink}</link>
+  <link>${permalink}</link>
   <dc:date>${thing._date.isoformat()}-0700</dc:date>
   <description>${body|h}</description>
 </item>