finish the interpreter bones

src/main/java/com/craftinginterpreters/lox/Interpreter.java

@@ -61,6 +61,7 @@ public class Interpreter implements Expr.Visitor<Object> {
       }
       case SLASH -> {
         checkNumberOperand(expr.operator, left, right);
+        if (((Double) right) == 0D) throw new RuntimeError(expr.operator, "Division by Zero.");
         yield (double) left / (double) right;
       }
       case STAR -> {