Add mdn link for map function (#29883)

Add resources section and include mdn link for map function

guide/english/javascript/es6/map-function/index.md

@@ -27,3 +27,7 @@ const myArray_2 = myArray_1.map(el => el * 2);
 `myArray_2` will contain the elements: `[2, 4, 6, 8]`
 
 `map()` is a method of the `Array` object, so to pass that function to an iterable object it is necessary to make the object an Array.
+
+### Resources:
+
+ [MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map)