def add_subcommand_formatting(self, command):
        """Adds formatting information on a subcommand.

        The formatting should be added to the :attr:`paginator`.

        The default implementation is the prefix and the :attr:`Command.qualified_name`
        optionally followed by an En dash and the command's :attr:`Command.short_doc`.

        Parameters
        -----------
        command: :class:`Command`
            The command to show information of.
        """
        fmt = '{0}{1} \N{EN DASH} {2}' if command.short_doc else '{0}{1}'
        self.paginator.add_line(fmt.format(self.clean_prefix, command.qualified_name, command.short_doc))