[3.15] Add a security warning about pydoc's HTTP server (#150573)

(cherry picked from commit 5535c1f)

Co-authored-by: Stan Ulbrych <stan@python.org>

Author: miss-islington

Doc/library/pydoc.rst

@@ -68,6 +68,11 @@ will start a HTTP server on port 1234, allowing you to browse the
 documentation at ``http://localhost:1234/`` in your preferred web browser.
 Specifying ``0`` as the port number will select an arbitrary unused port.
 
+.. warning::
+
+   The :mod:`!pydoc` HTTP server is intended for local use during
+   development and is not suitable for production use.
+
 :program:`python -m pydoc -n <hostname>` will start the server listening at the given
 hostname.  By default the hostname is 'localhost' but if you want the server to
 be reached from other machines, you may want to change the host name that the