bpo-41282: Add deprecation warning and docs for distutils (PEP 632) (GH-24355)

diff --git a/Doc/library/distutils.rst b/Doc/library/distutils.rst
index 62abc85..31c4ae5 100644
--- a/Doc/library/distutils.rst
+++ b/Doc/library/distutils.rst
@@ -9,6 +9,11 @@
 
 --------------
 
+:mod:`distutils` is deprecated with removal planned for Python 3.12.
+See the :ref:`What's New <distutils-deprecated>` entry for more information.
+
+--------------
+
 The :mod:`distutils` package provides support for building and installing
 additional modules into a Python installation.  The new modules may be either
 100%-pure Python, or may be extension modules written in C, or may be