Add links from builtins module docs to built-in functions and constants docs
diff --git a/Doc/library/builtins.rst b/Doc/library/builtins.rst
index c495728..d4199d2 100644
--- a/Doc/library/builtins.rst
+++ b/Doc/library/builtins.rst
@@ -7,7 +7,9 @@
This module provides direct access to all 'built-in' identifiers of Python; for
example, ``builtins.open`` is the full name for the built-in function
-:func:`open`.
+:func:`open`. See :ref:`built-in-funcs` and :ref:`built-in-consts` for
+documentation.
+
This module is not normally accessed explicitly by most applications, but can be
useful in modules that provide objects with the same name as a built-in value,
diff --git a/Doc/library/constants.rst b/Doc/library/constants.rst
index 51a1c26..fa61f68 100644
--- a/Doc/library/constants.rst
+++ b/Doc/library/constants.rst
@@ -1,3 +1,5 @@
+.. _built-in-consts:
+
Built-in Constants
==================