Merge pull request #14188 from pytest-dev/patchback/backports/9.0.x/3c37b551e71c8b18c5323dac8a27d248bb98a5a9/pr-14184

[PR #14184/3c37b551 backport][9.0.x] doc: add seealso link to src-layout vs flat-layout discussion

Author: webknjaz

doc/en/explanation/goodpractices.rst

@@ -150,6 +150,11 @@ which are better explained in this excellent `blog post`_ by Ionel Cristian Măr
     See :ref:`pytest vs python -m pytest` for more information about the difference between calling ``pytest`` and
     ``python -m pytest``.
 
+.. seealso::
+
+    :doc:`packaging:discussions/src-layout-vs-flat-layout`
+        The Python Packaging User Guide discusses the trade-offs between the ``src`` layout and ``flat`` layout.
+
 Tests as part of application code
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^