Automatic joining of lists, blockquotes, and similar

@marijn I believe my current triggers are:

  • deleting empty line
  • backspace (joinBackward)
  • deleting forward (joinForward)
  • wrapping in a list item

This gets into another example of why I want transform helpers. I’ve setup my list commands to do the normal operations of the above triggers PLUS they call transform helper versions of joinUp and joinDown. That way all operations are handled within a single transform.