Add code tabs for _tour/nested-functions

Author: flomebul

_tour/nested-functions.md

@@ -12,22 +12,48 @@ redirect_from: "/tutorials/tour/nested-functions.html"
 
 In Scala it is possible to nest method definitions. The following object provides a `factorial` method for computing the factorial of a given number:
 
+{% tabs Nested_functions_definition class=tabs-scala-version %}
+
+{% tab 'Scala 2' for=Nested_functions_definition %}
 ```scala mdoc
- def factorial(x: Int): Int = {
-    def fact(x: Int, accumulator: Int): Int = {
-      if (x <= 1) accumulator
-      else fact(x - 1, x * accumulator)
-    }  
-    fact(x, 1)
- }
-
- println("Factorial of 2: " + factorial(2))
- println("Factorial of 3: " + factorial(3))
+def factorial(x: Int): Int = {
+  def fact(x: Int, accumulator: Int): Int = {
+    if (x <= 1) accumulator
+    else fact(x - 1, x * accumulator)
+  }  
+  fact(x, 1)
+}
+
+println("Factorial of 2: " + factorial(2))
+println("Factorial of 3: " + factorial(3))
 ```
+{% endtab %}
+
+{% tab 'Scala 3' for=Nested_functions_definition %}
+```scala
+def factorial(x: Int): Int =
+  def fact(x: Int, accumulator: Int): Int =
+    if x <= 1 then accumulator
+    else fact(x - 1, x * accumulator)
+  fact(x, 1)
+
+println("Factorial of 2: " + factorial(2))
+println("Factorial of 3: " + factorial(3))
+
+```
+{% endtab %}
+
+{% endtabs %}
 
 The output of this program is:
 
+{% tabs Nested_functions_result %}
+
+{% tab 'Scala 2 and 3' for=Nested_functions_result %}
 ```
 Factorial of 2: 2
 Factorial of 3: 6
 ```
+{% endtab %}
+
+{% endtabs %}