Emphasize MyST, various other improvements #395

	# This is a basic workflow to help you get started with Actions

	name: test
	on: [push, pull_request]
	jobs:
	test:
	runs-on: ubuntu-latest

	strategy:
	matrix:
	sphinx_version: ["", "~=6.0.0", "~=5.0.0"]
	python_version: ["3.8", "3.10", '3.x']
	exclude:
	- {sphinx_version: "~=6.0.0", python_version: '3.8'}
	# - {sphinx_version: "~=4.0.0", python_version: '3.10'}
	# - {sphinx_version: "~=3.0.0", python_version: '3.x'}
	include:
	#- {sphinx_version: "~=3.0.0", python_version: '3.6'}
	- {sphinx_version: "~=4.0.0", python_version: '3.8'}

	# Steps represent a sequence of tasks that will be executed as part of the job
	steps:
	# Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
	- uses: actions/checkout@v4
	- name: Install Python
	uses: actions/setup-python@v4
	with:
	python-version: ${{ matrix.python_version }}
	- name: Install dependencies
	run: \|
	pip install sphinx${{matrix.sphinx_version}} -r requirements.txt .
	# jinja2 broke on 2022-03-24
	# https://github.com/sphinx-doc/sphinx/issues/10291
	# https://github.com/sphinx-doc/sphinx/issues/10289
	# Unsure of long-term plan here.
	if [ -n "{{matrix.sphinx_version}}" ] ; then
	pip install "jinja2<3.1"
	fi
	- name: List dependency versions
	run: \|
	python -V
	pip list

	# Runs a set of commands using the runners shell
	- name: Build and fail on errors
	run: \|
	make html SPHINXOPTS="-W --keep-going -T -v"

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