Update docs

Now that they're building with Hatch, update them to reflect updated
usage.

doc/hacking/contributing.rst

@@ -30,26 +30,22 @@ Python sources
 The code base follows `pep8 <https://www.python.org/dev/peps/pep-0008/>`_ guidelines with lines
 wrapping at the 79th character. You can verify that the code follows the conventions with::
 
-    $ pycodestyle --ignore=E252,W503,W504 spinach tests
+    $ hatch run pep8
 
 Running tests is an invaluable help when adding a new feature or when refactoring. Try to add the
-proper test cases in ``tests/`` together with your patch. The test suite can be run with pytest::
+proper test cases in ``tests/`` together with your patch.  Because the Redis broker tests require
+a running Redis server, there is a convenience `pyproject.toml` that runs all the tests and pep8
+checks for you after starting Redis in a container via docker-compose.  Simply running::
 
-    $ pytest tests
-
-Because the Redis broker tests require a running Redis server, there is also a convenience
-`tox.ini` that runs all the tests and pep8 checks for you after starting Redis in a container via
-docker-compose.  Simply running::
-
-    $ tox
+    $ hatch run py3
 
 will build a virtualenv, install Spinach and its dependencies into it, start the Redis server in
-the container, and run tests and pycodestyle, tearing down the Redis server container when done.
+the container, and run tests and pep8, tearing down the Redis server container when done.
 
 Compatibility
 -------------
 
-Spinach runs on all versions of Python starting from 3.6. Tests are run via GitHub actions to
+Spinach runs on all versions of Python starting from 3.8. Tests are run via GitHub actions to
 ensure that.
 
 Documentation sources
@@ -61,7 +57,6 @@ with `Sphinx <http://www.sphinx-doc.org/en/stable/index.html>`_.
 
 If you modify the docs, make sure it builds without errors::
 
-    $ cd doc/
-    $ make html
+    $ hatch run docs:build html
 
 The generated HTML pages should land in ``doc/_build/html``.