def create_file_name(path, start):
    """Create the name of rst file.

    Example:
    resources.libraries.python.honeycomb.rst
    tests.perf.rst

    :param path: Path to a module to be documented.
    :param start: The first directory in path which is used in the file name.
    :type path: str
    :type start: str
    :returns: File name.
    :rtype: str
    """
    dir_list = path.split('/')
    start_index = dir_list.index(start)
    return ".".join(dir_list[start_index:-1]) + ".rst"