What needs to be done for Atom/extensions to understand Common Mark #2

Here is the CommonForm github: https://github.com/commonform

And this is the specification for CommonMark: https://type.commonform.org/

CommonMark is very closely based on Markdown, so most of it will work automatically.

The test is that our customised version of Atom will read, and can edit, a test document and understand and deal appropriately with CommonMark formatting.

There is a test form here:
https://github.com/commonform/commonform.org/tree/main/forms/test

And this is a live form we can also use for testing:
https://github.com/commonform/commonform.org/blob/main/forms/waypoint/waypoint-nda/2e.md

I'll set up issues for each type of functionality we want to implement.

As a starting point we can extend the markdown-preview package. It uses the marked package to parse the MarkDown text and render the HTML content, so we can replace it with the commonmark.js package in order to parse the CommonMark text.