This works, but there are probably interesting edge cases around how it
works when directly adjacent to other paragraphs. I will have to think
about it a bit. This wrapping code in general would benefit from term
queries.
Perhaps violating the principle of least astonishment quite severely is
the fact that "> a" and ">" are detected as preformatted, but ">a" is
normal wrapped text. Supporting both ">a" and "> a" leads to
nonobvious whitespace behavior, but this code should not be able to
runtime error outside of the writer dying. This may be reevaluated in
the future, but I will leave it as-is for now.