Use minimal sized paragraph for custom cell end

[Alan-M-Thomaz]

Custom table cells, have added an empty paragraph at end, if last content is not an paragraph, is kinda annoying to get some blank space coming from "no where" ( i need to look in the source code do find where is was actually coming from).

It would be good, if was styled to have line zero by default, in the end it will not really be zero, but, minimal, but better than entire line, and letting it in a style, so that it can be edited, if someone wants a different behavior on it.