Update comment on type error for .slice() method

Clarified the error message explanation regarding the use of .slice() on numbers.

Author: anitahy73

Sprint-2/2-mandatory-errors/3.js

@@ -8,4 +8,4 @@ console.log(last4Digits);
 // Consider: Why does it give this error? Is this what I predicted? If not, what's different?
 // Then try updating the expression last4Digits is assigned to, in order to get the correct value
 
-// The .slice() method works on strings, but numbers don't have a .slice() method and it will cause this error : cardNumber.slice is not a function
+// The .slice() method works on strings, but numbers don't have a .slice() method and it will cause this error : cardNumber.slice is not a function and I think it's kind of type error.