Doc: add What's New in Python 3.5 to whatsnew index
diff --git a/Doc/whatsnew/index.rst b/Doc/whatsnew/index.rst
index 29902e4..edb5502 100644
--- a/Doc/whatsnew/index.rst
+++ b/Doc/whatsnew/index.rst
@@ -11,6 +11,7 @@
 .. toctree::
    :maxdepth: 2
 
+   3.5.rst
    3.4.rst
    3.3.rst
    3.2.rst