Nested bullets not correctly converted from MarkDown to oBook

[dosumis]

There is a problem with numbers and indentation in conversion to the oBook.

e.g.

https://oboacademy.github.io/obook/howto/merge-terms/

-->

Guidance is needed for writing Markdown for conversion (or added here if not already in place) and affected docs should be updated.

[balhoff]

@dosumis you might be running into the same issue I did: #346

The short answer is be sure to use 4 spaces for indentation, even though the GitHub preview indents correctly with 2 spaces.

[matentzn]

Fixed that page now.