Add docs for print_function and future_builtins. Fixes #2442.
diff --git a/Doc/library/python.rst b/Doc/library/python.rst
index 3b58eee..d9a37bb 100644
--- a/Doc/library/python.rst
+++ b/Doc/library/python.rst
@@ -14,6 +14,7 @@
 
    sys.rst
    __builtin__.rst
+   future_builtins.rst
    __main__.rst
    warnings.rst
    contextlib.rst