docs: def escape_code_start(source, ext, language='python'):
      """Escape code start with '# '"""
      parser = StringParser(language)
      for pos, line in enumerate(source):
          if not parser.is_quoted() and is_escaped_code_start(line, ext):
              source[pos] = _SCRIPT_EXTENSIONS.get(ext, {}).get('comment', '#') + ' ' + line
          parser.read_line(line)
      return source