Pyromark

- Rebuild with updated Rust compiler and updated dependencies.

- Add CLI.
- Add typing.final to pyromark.Markdown.
- Update dependencies.

- Use enum.IntFlag instead of a string sequence to define extensions.
- Fix pyromark.Markdown's \_\_module\_\_ attribute.
- New full-fledged documentation and docstrings instead of README.md.

- Rebuild with PyPy 3.10 wheels for x86_64 and i686.
- Update dependencies.

- Update dependencies (most importantly, PyO3 from 0.18.3 to 0.19.0).

- Update pulldown-cmark from 0.9.2 to 0.9.3.