add since doc for subant

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@416042 13f79535-47bb-0310-9956-ffa450edef68

docs/manual/CoreTasks/subant.html

@@ -55,6 +55,7 @@
                 <code>target</code> if it invokes the same build file it is
                 part of.</strong>
         </p>
+        <p><em>Since Ant 1.6</em></p>
     <table border="0" cellspacing="0" cellpadding="2" width="100%">
       <!-- Subsection heading -->
       <tr><td bgcolor="#828DA6">
@@ -528,7 +529,7 @@
   <tr>
     <td>
       <div align="center"><font color="#525D76" size="-1"><em>
-        Copyright &copy; 2000-2005, The Apache Software Foundation. All Rights Reserved.
+        Copyright &copy; 2000-2006, The Apache Software Foundation. All Rights Reserved.
       </em></font></div>
     </td>
   </tr>