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

@@ -1,29 +1,33 @@
----
-title: Map Function
----
-
-## The Map Function
-
-The `map()` function is used for creating a new array from an existing one, applying a function to each one of the elements of the first array.
-
-The original syntax of the map function is:
-```javascript
-  let new_arr = arr.map(function callback(currentValue, index, array) {
-                  // Do some stuff with currentValue (index and array are optionals)
-                })
-```
-* `new_arr` - the new array that is returned
-* `ar`r - the array to run the map function on
-* `currentValue` - the current value being processed
-* `index` - the current index of the value being processed
-* `array` - the original array
-
-### Example (ES6):
-
-```javascript
-const myArray_1 = [1, 2, 3, 4];
-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.
+---
+title: Map Function
+---
+
+## The Map Function
+
+The `map()` function is used for creating a new array from an existing one, applying a function to each one of the elements of the first array.
+
+The original syntax of the map function is:
+```javascript
+  let new_arr = arr.map(function callback(currentValue, index, array) {
+                  // Do some stuff with currentValue (index and array are optionals)
+                })
+```
+* `new_arr` - the new array that is returned
+* `ar`r - the array to run the map function on
+* `currentValue` - the current value being processed
+* `index` - the current index of the value being processed
+* `array` - the original array
+
+### Example (ES6):
+
+```javascript
+const myArray_1 = [1, 2, 3, 4];
+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)