Fix invalid link fragment by adding id to header

The header contains a dash '-' that causes the automatically generated fragment to don't match the link to the header:
	generated fragment link: '#the-module-pattern---iifes'
	correct link: '#the-module-pattern-iifes'
By using the correct link as an id in the header both links will match

javascript/organizing_your_javascript_code/factory_functions_and_module_pattern.md

@@ -224,7 +224,7 @@ function createPlayer (name, level) {
 }
 ```
 
-### The module pattern - IIFEs
+### The module pattern - IIFEs {#the-module-pattern-iifes}
 
 <div class="lesson-note lesson-note--warning" markdown="1" >