Automate test using `pyproject.toml`

[ZackeryRSmith]

Currently, testing the lexer is done manually via test.py; however, Pygments requires lexers to use Tox for automated testing.

To ensure our lexer can be accepted upstream, we must migrate the testing setup to Tox.

[ZackeryRSmith]

Sorry to correct myself, they require an example file/snippet. Let's repurpose this issue; instead, let's focus on utilizing our pyproject.toml to run an automated test.