Well, I mean technically, your version control could take care of it even after the editor would save the file after every keystroke. "Ooops, I didn't mean to

Well, I mean technically, your version control could take care of it even after the editor would save the file after every keystroke. "Ooops, I didn't mean to do that" is one of the primary reasons why "Undo" was invented. It's something that should be fixed in the editor, not offloaded to the version control system, especially since there's no reason to assume that every single plain text file you'll ever edit is under version control.