code: func (l *List) PageDown() {
  	start := l.start + l.size
  	max := len(l.scope) - l.size
  
  	switch {
  	case len(l.scope) < l.size:
  		l.start = 0
  	case start > max:
  		l.start = max
  	default:
  		l.start = start
  	}
  
  	cursor := l.start
  
  	if cursor == l.cursor {
  		l.cursor = len(l.scope) - 1
  	} else if cursor > l.cursor {
  		l.cursor = cursor
  	}
  }
docs: // PageDown moves the visible list forward by x items. Where x is the size of
  // the visible items on the list. The selected item becomes the first visible
  // item.