Add a typing stack after each stack.

async def flush(self, request: Request, stacks: List[Stack]):
        """
        Add a typing stack after each stack.
        """

        ns: List[Stack] = []

        for stack in stacks:
            ns.extend(self.typify(stack))

        if len(ns) > 1 and ns[-1] == Stack([lyr.Typing()]):
            ns[-1].get_layer(lyr.Typing).active = False

        await self.next(request, ns)