Add new tasks to overview

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@273542 13f79535-47bb-0310-9956-ffa450edef68

docs/manual/tasksoverview.html

@@ -449,12 +449,26 @@ documentation.</p>
     <th>Description</th>
   </tr>
 
+  <tr valign="top">
+    <td nowrap><a href="OptionalTasks/attrib.html">Attrib</a></td>
+    <td><p>Changes the permissions and/or attributes of a file or all
+    files inside the specified directories. Currently, it has effect
+    only under Windows.</p></td>
+  </tr>
+
   <tr valign="top">
     <td nowrap><a href="CoreTasks/checksum.html">Checksum</a></td>
     <td><p>Generates a checksum for a file or set of files. This task can
      also be used to perform checksum verifications.</p></td>
   </tr>
 
+  <tr valign="top">
+    <td nowrap><a href="OptionalTasks/chgrp.html">Chgrp</a></td>
+    <td><p>Changes the group ownership of a file or all files inside
+    the specified directories. Currently, it has effect only under
+    Unix.</p></td>
+  </tr>
+
   <tr valign="top">
     <td nowrap><a href="CoreTasks/chmod.html">Chmod</a></td>
     <td><p>Changes the permissions of a file or all files inside the
@@ -463,6 +477,13 @@ documentation.</p>
     <i>chmod</i> command.</p></td>
   </tr>
 
+  <tr valign="top">
+    <td nowrap><a href="OptionalTasks/chown.html">Chown</a></td>
+    <td><p>Changes the owner of a file or all files inside the
+    specified directories. Currently, it has effect only under
+    Unix.</p></td>
+  </tr>
+
   <tr valign="top">
     <td nowrap><a href="CoreTasks/concat.html">Concat</a></td>
     <td><p>Concatenates multiple files into a single one or to Ant's