menusectionbox: Improve circular button spacing
In the n == 2 case, we want to avoid the buttons being drawn all the way out to the ends of the box, but in the n >= 3 case, that is exactly what we want for the first and last button.
In the n == 2 case, we want to avoid the buttons being drawn all the way out to the ends of the box, but in the n >= 3 case, that is exactly what we want for the first and last button.