Editor should stop list when enter is pressed on blank entries twic

[chasinglogic]

When a user is created a list we automatically add a - to the beginning of the line. When a user presses this twice without entry we should stop adding to the list and clean up the erroneous entries. For example:

- item 1
- item 2
- 

If the user presses enter here they will get

- item 1
- item 2
- 
- 

The expected behavior that if they press enter again from this position they will end up with this:

- item 1
- item 2

| <- cursor here

This should work for numbered lists as well