Update diceClass.java

If you extend this class to create DoubleDice and TripleDice, you can at the minimum override the toString to describe the object more precisely...such as Triple Dice instread of number of dice: 3.

If you understand inheritance and see no needs to do so, that is fine.  I do like for those who are lost to be able to do an actual implementation so that they can understand the concept more concretely.