Change "add" to "add/remove" so you know how to remove insights

Created by: Joelkw

@AlicjaSuska @vovakulikov can you review this?

@AlicjaSuska I think since this is the only way to remove insights we want users to know that in the label, not have to mentally connect the dots of "I saw a checkbox on the add screen...oh, a checkbox goes both ways" to figure out how to remove. Attached is a modified-in-the-browser-elements shot of what I assume it will render as.

@vovakulikov dumb question, the slash won't break our JSX right? 99% sure it won't but just confirming.