Correct %exception documentation so no memory is leaked - bug #2903761

git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk@11759 626c5289-ae23-0410-ae9c-e8d60b6d4f22

Doc/Manual/Customization.html

@@ -53,6 +53,21 @@ The <tt>%exception</tt> directive allows you to define a general purpose excepti
 handler. For example, you can specify the following:
 </p>
 
+<div class="code"><pre>
+%exception {
+    try {
+        $action
+    }
+    catch (RangeError) {
+        ... handle error ...
+    }
+}
+</pre></div>
+
+<p>
+How the exception is handled depends on the target language, for example, Python:
+</p>
+
 <div class="code"><pre>
 %exception {
     try {
@@ -60,7 +75,7 @@ handler. For example, you can specify the following:
     }
     catch (RangeError) {
         PyErr_SetString(PyExc_IndexError,"index out-of-bounds");
-        return NULL;
+        SWIG_fail;
     }
 }
 </pre></div>