Modifies inline patterns.

def extendMarkdown(self, md, md_globals):
        """Modifies inline patterns."""
        md.inlinePatterns.add('del', SimpleTagPattern(DEL_RE, 'del'), '<not_strong')
        md.inlinePatterns.add('ins', SimpleTagPattern(INS_RE, 'ins'), '<not_strong')
        md.inlinePatterns.add('mark', SimpleTagPattern(MARK_RE, 'mark'), '<not_strong')