doc: PEP 8 compliance is required (#25524)

docs/docsite/rst/dev_guide/developing_modules_checklist.rst

@@ -108,7 +108,7 @@ The complete module metadata specification is here: `Ansible metadata block <htt
         main()
 
 * Try to normalize parameters with other modules, you can have aliases for when user is more familiar with underlying API name for the option
-* Being pep8 compliant is nice, but not a requirement. Specifically, the 80 column limit now hinders readability more that it improves it
+* Being `PEP 8 <https://www.python.org/dev/peps/pep-0008/>`_ compliant is a requirement. See :doc:`testing_pep8` for more information.
 * Avoid '`action`/`command`', they are imperative and not declarative, there are other ways to express the same thing
 * Do not add `list` or `info` state options to an existing module - create a new `_facts` module.
 * If you are asking 'how can I have a module execute other modules' ... you want to write a role

docs/docsite/rst/dev_guide/developing_modules_in_groups.rst

@@ -19,7 +19,7 @@ Before you start coding
 Although it's tempting to get straight into coding, there are a few things to be aware of first. This list of prerequisites is designed to help ensure that you develop high-quality modules that flow easily through the review process and get into Ansible more quickly.
 
 * Read though all the pages linked off :doc:`developing_modules`; paying particular focus to the :doc:`developing_modules_checklist`.
-* For new modules going into Ansible 2.4 we are raising the bar so they must pass ``pep8 --ignore=E402 --max-line-length=160`` cleanly.
+* For new modules going into Ansible 2.4 we are raising the bar so they must be PEP 8 compliant. See :doc:`testing_pep8` for more information.
 * Starting with Ansible version 2.4, all new modules must support Python 2.6 and Python 3.5+. If this is an issue, please contact us (see the "Speak to us" section later in this document to learn how).
 * All modules shipped with Ansible must be done so under the GPLv3 license. Files under the ``lib/ansible/module_utils/`` directory should be done so under the BSD license.
 * Have a look at the existing modules and how they've been named in the :doc:`../list_of_all_modules`, especially in the same functional area (such as cloud, networking, databases).