Cleans up trailing whitespace (#700)

_includes/comments.html

@@ -1,6 +1,6 @@
-{% if page.comments %}        
+{% if page.comments %}
   {% include disqus.html %}
   {% include fb-comment.html %}
   {% include staticman-comments.html %}
   {% include utterances-comment.html %}
-{% endif %}
+{% endif %}