Encapsulate ReST directive in Markdown with MyST

Source

ReST:

.. toctree::
caption: Episodes
maxdepth: 1

basics
creating-using-web
creating-using-desktop
contributing
doi
websites

MyST:

To use it, activate your dev env and pip install myst-parser.

```{toctree}
---
caption: Episodes
maxdepth: 1
---

basics
creating-using-web
creating-using-desktop
contributing
doi
websites
```