This patch fixes hard-wrapped block contexts (blockquotes, numbered and bullet lists) in Markdown not getting properly highlighted: now the whole paragraph gets highlighted instead of just the first line.
Side effect: with this patch an empty line is needed to change the highlighting context which is in accordance with http://daringfireball.net/projects/markdown/syntax: “A paragraph is simply one or more consecutive lines of text, separated by one or more blank lines.”

Several hours of usage revealed no errors so far.