Restore coda to readme; useful in jar help output

Author: sideshowbarker

README.md

@@ -131,3 +131,8 @@ executable provides the following options:
 
     Shows the vnu.jar version number.
 
+To provide browser-based checking of documents over the Web, see [Web-based
+checking with vnu.war or vnu.jar][13].
+
+   [13]: http://validator.github.io/service.html
+

index.html

@@ -152,3 +152,6 @@ <h4 id="version">--version</h4>
 </pre>
 </section>
 </div>
+
+<p>To provide browser-based checking of documents over the Web, see
+<a href="http://validator.github.io/service.html">Web-based checking with vnu.war or vnu.jar</a>.