Support for Jupyter-Book

[jonathf]

What would you like to see

I am using Jupyter-Book as a Sphinx wrapper. It would be awesome to see Esbonio support this format as well as native Sphinx.

When I open an RST-file in a Jupyter-Book project now, I get an error that it can not find the file conf.py.

The differences between Sphinx and Jupyter-Book is minor:

• Sphinx uses conf.py and index.rst for configuration, while Jupyter-Book uses _config.yml and _toc.yml.
• The build tools are sphinx-build and jupyter-book build, but they support the same functionality
• Jupyter-Book installs a few extra plugins by default, like MyST.