explain why you cant delete *~ so easily

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@271609 13f79535-47bb-0310-9956-ffa450edef68

docs/manual/CoreTasks/delete.html

@@ -16,6 +16,12 @@ When specifying a set of files, empty directories are <i>not</i> removed by
 default.
 To remove empty directories, use the <code>includeEmptyDirs</code> attribute.
 </p>
+<p>
+If you use this task to delete temporary files created by editors and it doesnt
+seem to work, read up on the 
+<a href="../dirtasks.html#defaultexcludes">default exclusion set</a> then at the option
+down below to disable this feature.
+ 
 <h3>Parameters</h3>
 <table border="1" cellpadding="2" cellspacing="0">
   <tr>