Move backward to start of paragraph.
With argument ARG, do it ARG times;
a negative argument ARG = -N means move forward N paragraphs.
A paragraph start is the beginning of a line which is a
`paragraph-start' or which is ordinary text and follows a
`paragraph-separate'ing line; except: if the first real line of a
paragraph is preceded by a blank line, the paragraph starts at that
See `forward-paragraph' for more information.