when switching to a prompt without a right prompt, after a prompt with a `fish_right_prompt`, you get a nasty result. e.g.: ``` $ fish_config prompt choose disco $ fish_config prompt choose default ``` <img width="717" alt="Screen Shot 2021-09-24 at 9 45 08 AM" src="https://user-images.githubusercontent.com/291142/134711565-479c2695-29a5-4e4c-8028-56f6e7bc4330.png">