Modify rule S2004: Increase default threshold to four nested functions (

#3643)

rules/S2004/javascript/rule.adoc

@@ -8,14 +8,16 @@ This can make it difficult for other developers or even yourself to understand a
 
 === Noncompliant code example
 
-With the default threshold of 3 levels:
+With the default threshold of 4 levels:
 
 [source,javascript]
 ----
 function f() {
   function f_inner() {
     function f_inner_inner() {
-      function f_inner_inner_inner() { // Noncompliant
+      function f_inner_inner_inner() {
+        function f_inner_inner_inner_inner() { // Noncompliant
+        }
       }
     }
   }