A couple of README issues

[saiwing-yeung]

🐛 Bug

There are a couple of documentation issues in the README.

To Reproduce

Steps to reproduce the behavior:

The README says

This repo in main branch contain only python scripts with markdown extensions, and notebooks are generated in special publication branch, so no raw notebooks are accepted as PR. On the other hand we highly recommend creating a notebooks and convert it script with jupytext as

jupytext --set-formats ipynb,py:percent my-notebook.ipynb

Expected behavior

1. In "On the other hand we highly recommend creating a notebooks and convert it script with jupytext as", there are a couple of issues. It should be just "notebooks" instead of "a notebooks" and something like "convert it using jupytext".
2. The jupytext command also doesn't work because the command tries to read an ipynb file when we only provide Python scripts. Also I think for most users they don't need to sync the notebook and Python script and just need to convert from a script to a notebook. So it might be simpler to give a command like jupytext --output input.py output.ipynb

[Borda]

Thank you for taking the time and validate our readme, could you please send a PR with suggestions? :)