Explained the error message in 1.js

Author: habohlin

Sprint-2/2-mandatory-errors/1.js

@@ -3,4 +3,6 @@
 let age = 33;
 age = age + 1;
 
-// Answer: I changed the const to let, so the variable age becomes reassignable
+// Answer: I got the error message TypeError: Assignment to constant variable.
+// That is because age was declared using const, which makes it non-reassignable.
+// I changed the const to let, so the variable age becomes reassignable