code: private Node rotateRight(Node node) {
          Node rightChild = node.right;
          node.right = rightChild.left;
          rightChild.left = node;
          node.height = calculateHeight(getHeight(node.left), getHeight(node.right));
          rightChild.height = calculateHeight(getHeight(rightChild.right), node.height);
          return rightChild;
      }
docs: Rotates the given binary tree node with the right child. At the end of this operation:
  * The Right Child's left node is the Given Node
  * The Given Node's Right child is the Right Child's original Left Child.