Typo

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@274293 13f79535-47bb-0310-9956-ffa450edef68

docs/manual/developlist.html

@@ -13,7 +13,7 @@
 <h3>Developing with Ant</h3>
 
 <a href="develop.html#writingowntask">Writing Your Own Task</a><br>
-<a href="base_task_classes.html">Tasks Designed for Extensiton</a><br>
+<a href="base_task_classes.html">Tasks Designed for Extension</a><br>
 <a href="develop.html#buildevents">Build Events</a><br>
 <a href="develop.html#integration">Source-code Integration</a><br>
 <a href="inputhandler.html">InputHandler</a><br>