doc: Strip trailing whitespace; other revisions

Make some random and non-comprehensive changes to the
template functions documentation to make them more
consistent.

docs/layouts/shortcodes/fileindex.html

@@ -11,6 +11,6 @@
                 <td>
                     <a href="{{$url}}{{.Name | urlize }}"> {{.Name}}</a>
                     </td>
-            </tr> 
+            </tr>
 	 {{ end }}
 </table>

docs/layouts/showcase/thumbnail.html

@@ -3,7 +3,7 @@
     <a href="{{ .Params.sitelink }}"><img class="img-responsive img-rounded" style="width:100%;" src="{{ .Params.thumbnail }}" alt="{{ .Description }}"></a>
     <h4>
       <a href="{{ .Params.sitelink }}">{{ .Title }}</a>
-      {{ if (isset .Params "sourcelink") }} 
+      {{ if (isset .Params "sourcelink") }}
       <a href="{{ .Params.sourcelink }}" class="small pull-right">source</a>
       {{ end }}
     </h4>