Add future_builtins.ascii().
diff --git a/Doc/library/future_builtins.rst b/Doc/library/future_builtins.rst
index d25aff7..6a1fdab 100644
--- a/Doc/library/future_builtins.rst
+++ b/Doc/library/future_builtins.rst
@@ -28,6 +28,14 @@
Available builtins are:
+.. function:: ascii(object)
+
+ Returns the same as :func:`repr`. In Python 3, :func:`repr` will return
+ printable Unicode characters unescaped, while :func:`ascii` will always
+ backslash-escape them. Using :func:`future_builtins.ascii` instead of
+ :func:`repr` in 2.6 code makes it clear that you need a pure ASCII return
+ value.
+
.. function:: filter(function, iterable)
Works like :func:`itertools.ifilter`.