FIX Uneccessary class replacement

Overly complex code example.

docs/en/02_Developer_Guides/05_Extending/05_Injector.md

@@ -125,15 +125,13 @@ An example using the `MyFactory` service to create instances of the `MyService`
 	Injector:
 	  MyService:
 	    factory: MyFactory
-	  MyFactory:
-	    class: MyFactoryImplementation
 
-**mysite/code/MyFactoryImplementation.php**
+**mysite/code/MyFactory.php**
 
 	:::php
 	<?php
 
-	class MyFactoryImplementation implements SilverStripe\Framework\Injector\Factory {
+	class MyFactory implements SilverStripe\Framework\Injector\Factory {
 
 		public function create($service, array $params = array()) {
 			return new MyServiceImplementation();
@@ -243,4 +241,4 @@ This is useful when writing test cases, as certain services may be necessary to
 ## API Documentation
 
 * [api:Injector]
-* [api:Factory]
+* [api:Factory]