Fix unfinished thought in xml overview page.  Suggested by Bo Bayles on docs@.
diff --git a/Doc/library/xml.rst b/Doc/library/xml.rst
index d2dafa4..e56eb2c 100644
--- a/Doc/library/xml.rst
+++ b/Doc/library/xml.rst
@@ -28,6 +28,7 @@
 The XML handling submodules are:
 
 * :mod:`xml.etree.ElementTree`: the ElementTree API, a simple and lightweight
+  XML processor
 
 ..