Deal with <num> better #1
Description
Currently, the interface leaves the content of <num> empty, and uses ::before in CSS to display the correct numbers as if they were list items. That's not compliant with the standard, which requires the text of the index number to appear inside the <num> tags. The solution will be to build something that listens for changes to the node tree, and then modifies the content of the <num> tags manually, based on attributes of their parents, etc. The ProseMirror forums suggest using the "addTransaction" features to pre-process changes to include the additional required changes to the content, so they will all be made, or not, at the same time.