fix spelling

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@547249 13f79535-47bb-0310-9956-ffa450edef68

docs/manual/OptionalTasks/script.html

@@ -140,7 +140,7 @@ Groups@Google: "Rhino, enum.js, JavaAdapter?"</a> by Norris Boyd in the newsgrou
     This means that it can be used to specify
     the classpath containing the language implementation for BSF
     or for JSR 223 managers.
-    This can be usefull if one wants
+    This can be useful if one wants
     to keep ${user.home}/.ant/lib free of lots of scripting language
     specific jar files.
   </p>