-u option is not needed with new versions of svn client

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@910670 13f79535-47bb-0310-9956-ffa450edef68

docs/ant_task_guidelines.html

@@ -416,7 +416,7 @@ that constitute part of the patch.
 <li><h3>Approach 2 - The Manual Way</h3>
 <p>
 Patches to existing files should be generated with
-<code>svn diff -u filename</code>
+<code>svn diff filename</code>
  and save the output to a file. If you want to get
 the changes made to multiple files in a directory , just use <code>cvs
 diff -u</code>.  Then, Tar and GZip the patch file as well as any new files