Add prediction comment explaining SyntaxError in 0.js

Author: moses77-boop

Sprint-3/1-key-errors/0.js

@@ -1,5 +1,7 @@
 // Predict and explain first...
 //  =============> write your prediction here
+// Prediction
+// A SyntaxError is thrown with message: Identifier 'str' has already been declared
 
 // call the function capitalise with a string input
 // interpret the error message and figure out why an error is occurring