Make lark.lark parse the same grammar as load_grammar.py, and make grammar.md document it more fully. #1467

	name: Tests
	on: [push, pull_request]

	jobs:
	build:
	# runs-on: ubuntu-latest
	runs-on: ubuntu-20.04 # See https://github.com/actions/setup-python/issues/544
	strategy:
	matrix:
	python-version: ["3.6", "3.7", "3.8", "3.9", "3.10", "3.11", "3.12", "pypy-3.7"]

	steps:
	- uses: actions/checkout@v3
	with:
	submodules: recursive
	- name: Set up Python ${{ matrix.python-version }}
	uses: actions/setup-python@v4
	with:
	python-version: ${{ matrix.python-version }}
	- name: Install dependencies
	run: \|
	python -m pip install --upgrade pip
	pip install -r test-requirements.txt
	- name: Run tests
	run: \|
	python -m tests

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