Markdown-it-py

✨ NEW: Add `anchors_plugin` for headers, which can produce:

html
<h1 id="title-string">Title String <a class="header-anchor" href="title-string">¶</a></h1>

🐛 Fixed an undefined variable in the reference block.

🐛 Fixed an `IndexError` in `container_plugin`, when there is no newline on the closing tag line.

⬆️ UPGRADE: attrs -> v20

This is not breaking, since it only deprecates Python 3.4 (see [CHANGELOG.rst](https://github.com/python-attrs/attrs/blob/master/CHANGELOG.rst))

Added ✨

- `deflist` and `dollarmath` plugins (see [plugins list](https://markdown-it-py.readthedocs.io/en/latest/plugins.html)).

Improved 👌

- Added benchmarking tests and CI (see <https://executablebooks.github.io/markdown-it-py/dev/bench/>)
- Improved performance of computing ordinals (=> 10-15% parsing speed increase).
Thanks to [sildar](https://github.com/sildar)!

Fixed 🐛

- Stopped empty lines at the end of the document, after certain list blocks, raising an exception (36).
- Allow myst-role to accept names containing digits (0-9).

Added ✨

- `containers` plugin (see [plugins list](https://markdown-it-py.readthedocs.io/en/latest/plugins.html))

Documented 📚

- Plugins and improved contributing section