Add more TOC to the whatsnew index page.
diff --git a/Doc/whatsnew/index.rst b/Doc/whatsnew/index.rst
index 07552a4..ec45756 100644
--- a/Doc/whatsnew/index.rst
+++ b/Doc/whatsnew/index.rst
@@ -9,7 +9,7 @@
 anyone wishing to stay up-to-date after a new release.
 
 .. toctree::
-   :maxdepth: 1
+   :maxdepth: 2
 
    2.7.rst
    2.6.rst