Displays characters summary.

def _charSummary(self, char_count, block_count=None):
        """
        Displays characters summary.
        """
        if not self._display['omit_summary']:
            if block_count is None:
                print('Total code points:', char_count)
            else:
                print('Total {0} code point{1} in {2} block{3}'.format(
                    char_count,
                    's' if char_count != 1 else '',
                    block_count,
                    's' if block_count != 1 else ''
                ))