Refs #32074 -- Recommended aiosmtpd for minimal SMTP server.

Follow up to 569a33579c3cca5f801c544d9b52a34e3c779424.

docs/topics/email.txt

@@ -672,15 +672,19 @@ to a file that can be inspected at your leisure.
 
 Another approach is to use a "dumb" SMTP server that receives the emails
 locally and displays them to the terminal, but does not actually send
-anything. Python has a built-in way to accomplish this with a single command::
+anything. The `aiosmtpd`_ package provides a way to accomplish this::
 
-    python -m smtpd -n -c DebuggingServer localhost:1025
+    python -m pip install aiosmtpd
 
-This command will start a minimal SMTP server listening on port 1025 of
+    python -m aiosmtpd -n -l localhost:8025
+
+This command will start a minimal SMTP server listening on port 8025 of
 localhost. This server prints to standard output all email headers and the
 email body. You then only need to set the :setting:`EMAIL_HOST` and
 :setting:`EMAIL_PORT` accordingly. For a more detailed discussion of SMTP
-server options, see the Python documentation for the :mod:`smtpd` module.
+server options, see the documentation of the `aiosmtpd`_ module.
+
+.. _aiosmtpd: https://aiosmtpd.readthedocs.io/en/latest/
 
 For information about unit-testing the sending of emails in your application,
 see the :ref:`topics-testing-email` section of the testing documentation.