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 c3a26f3..f793bae 100644
--- a/Doc/library/xml.rst
+++ b/Doc/library/xml.rst
@@ -29,6 +29,7 @@
 The XML handling submodules are:
 
 * :mod:`xml.etree.ElementTree`: the ElementTree API, a simple and lightweight
+  XML processor
 
 ..