lessThanOrEquals method
Returns true if the item values in the current list overlap or are all less than
the item values in the passed in list. None of the item values in the current list must
go above the item values in the passed in list. Equivalent to (list1 <= list2) in ink,
or LIST_MAX(list1) <= LIST_MAX(list2) && LIST_MIN(list1) <= LIST_MIN(list2).
Implementation
bool lessThanOrEquals(InkList otherList) {
if (otherList.isEmpty) return false;
if (isEmpty) return true;
return maxItem.value <= otherList.maxItem.value &&
minItem.value <= otherList.minItem.value;
}