Write a text file and provide feedback to the user.

        :param filename: The pathname of the file to write (a string).
        :param contents: The new contents of the file (a string).

def write_file(self, filename, contents):
        """
        Write a text file and provide feedback to the user.

        :param filename: The pathname of the file to write (a string).
        :param contents: The new contents of the file (a string).
        """
        logger.info("Writing file: %s", format_path(filename))
        contents = contents.rstrip() + b"\n"
        self.context.write_file(filename, contents)
        logger.debug("Wrote %s to %s.",
                     pluralize(len(contents.splitlines()), "line"),
                     format_path(filename))