Fix the default value for feature_namespaces, per discussions on the XML-SIG

mailing list.  This causes the docs to match the default implementation.

Doc/lib/xmlsaxhandler.tex

@@ -49,9 +49,9 @@ symbolic constants for the feature and property names.
 
 \begin{datadesc}{feature_namespaces}
   Value: \code{"http://xml.org/sax/features/namespaces"}\\
-  true: Perform Namespace processing (default).\\
+  true: Perform Namespace processing.\\
   false: Optionally do not perform Namespace processing
-         (implies namespace-prefixes).\\
+         (implies namespace-prefixes; default).\\
   access: (parsing) read-only; (not parsing) read/write
 \end{datadesc}