import re


def syntax_tweaks(lines):
    """
    Applies custom tweaks to the Markdown syntax.

    Namely, converts the Unicode bullet character (•) to a standard
    list-item marker (*) so that the CommomMark parser recognizes it
    as such — which it regrettably doesn't.
    """
    tweaked = [re.sub(r'^([ \t]*)•', r'\1*', line) for line in lines]
    return tweaked