Another check to help with paragraph depth parsing

This one confirms that collapsed markers make sense in that they are at least one paragraph level below the initial paragraph marker in the text.

See the test for a specific example; basically it has a broken citation, and we *don't* want to start a sub paragraph. I would normally suggest fixing the citation, but in this situation, the text is too free-form.

To complicate matters a wee bit, paragraph markers can be ambiguous, so we just verify that at least *one* potential paragraph level matching makes sense.