Add doco about new feature

git-svn-id: https://svn.apache.org/repos/asf/maven/maven-1/plugins/trunk@405259 13f79535-47bb-0310-9956-ffa450edef68

ant/xdocs/goals.xml

@@ -49,6 +49,7 @@
               <li>Download all required jar files</li>
               <li>Download and install Maven</li>
             </ul>
+          <p>The generated file is located at ${maven.ant.generate.dir}/${maven.ant.generate.script}. If the file already exists the plugin ask to the user if he wants to overwrite it (except if the property <code>maven.ant.generate.force</code> is setted to true).</p>
           </td>
         </tr>
         <tr>