Add some clarification to <antcall>'s docs.

PR: 12820


git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@273370 13f79535-47bb-0310-9956-ffa450edef68

docs/manual/CoreTasks/antcall.html

@@ -62,6 +62,18 @@ will be fixed and not overridable in the init task -or indeed in the "doSom
     <td align="center" valign="top">No</td>
   </tr>  
 </table>
+
+<h3>Note on <code>inheritRefs</code></h3>
+
+<p><code>&lt;antcall&gt;</code> will not override existing references,
+even if you set <code>inheritRefs</code> to true.  As the called build
+files is the same build file as the calling one, this means it will
+not override any reference set via an <code>id</code> attribute at
+all.  The only references that can be inherited by the child project
+are those defined by nested <code>&lt;reference&gt;</code> elements or
+references defined by tasks directly (not using the <code>id</code>
+attribute).</p>
+
 <h3>Parameters specified as nested elements</h3>
 <h4>param</h4>
 <p>Specifies the properties to set before running the specified target. See <a