Q5 ref link update

sadanandpai · web-flow · commit d59b9d94779b · 2021-07-09T23:48:51.000+05:30
diff --git a/challenges/functions-concepts.md b/challenges/functions-concepts.md
@@ -153,7 +153,7 @@ varArgsFunc("Hello", ",", "World", "!!!");
 ```
 
 ###### References
-- https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_syntax
+- https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/rest_parameters
 
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