Minor fix: create new todo on ENTER, but switch to the next empty one if any is present

Scenario You have 2 TODO entries, and your focus is on entry 2: [ walk the dog ] [ get groceries ] <focus On press ENTER, a third entry will be created, initialized to an empty value [ walk the dog ] [ get groceries ] [ // empty ] <focus You now shift focus to either entry 1 or 2 (let's say entry 2), and hit ENTER Current behavior: a 4th empty entry is created: before hitting ENTER: [ walk the dog ] [ get groceries ] <focus [ // empty ] after hitting ENTER: [ walk the dog ] [ get groceries ] [ // empty ] [ // empty ] <focus Suggested behavior: if there is an empty todo entry which index is higher of the currently selected one, hitting ENTER will focus that entry. Otherwise, it will create a new one at the bottom of the list (which already happens) before hitting ENTER: [ walk the dog ] [ get groceries ] <focus [ // empty ] after hitting ENTER: [ walk the dog ] [ get groceries ] [ // empty ] <focus