Add section numbering to some of the larger subdocuments.
diff --git a/Doc/using/index.rst b/Doc/using/index.rst
index ac5fd3c..6ce5a00 100644
--- a/Doc/using/index.rst
+++ b/Doc/using/index.rst
@@ -11,6 +11,7 @@
 
 
 .. toctree::
+   :numbered:
 
    cmdline.rst
    unix.rst