evil-org changes the behavior of o/O to create new headlines, plain list
items or table rows. I disable its new behavior in plain lists only.
This was done because:
1. It isn't uncommon to want o/O's default behavior in plain list bodies
of text. Unlike tables, where a new line in the middle of a table
doesn't make much sense.
2. M-RET/S-M-RET exists.