📝 Enable showing news categories in towncrier log

Resurrect docs interlinking

🔥 Get rid of the unused sphinx `Makefile`

Fixes #2424

It's been lost as a part of https://github.com/pypa/setuptools/pull/2097

ignore any exception when loading 2to3

Make an illustrative change notes guide in GH UI

Co-Authored-By: Thomas Hisch <thomas.hisch@ims.co.at>

Fixes #2394

This change places a `README.rst` document under `changelog.d/` dir in
order for GitHub to render it when users navigate to this location via
the web UI.

It also includes that into the dev guide in Sphinx docs.

This type is more appropriate for snippets containing shell commands
with leading prompts followed by their output. `bash` syntax used
earlier treats everything as a raw shell script contents highlighting
words like `for`.

But only under Python 3.5!

This change adds a role that links to the GitHub user Sponsors
page. If that page is not set up, it'll redirect to the GitHub user
profile page instead:

Links to https://github.com/sponsors/{{ username }} open as GitHub
Sponsors page if the target `username` has it enabled and redirect
to https://github.com/{{ username }} if it's disabled.

Extract ppc patch

Adding changes to support PPC64LE

Apply docs revamp

Enable flake8 and cov plugins only when installed.