fix(code): fix on clone usage

Author: Guikingone

service_container/injection_types.rst

@@ -261,21 +261,16 @@ this approach allow you to make a service immutable::
     {
         private $mailer;
         
-        public function __construct(?MailerInterface $mailer = null)
-        {
-            $this->mailer = $mailer;
-        }
-        
         /**
-         *
-         * The @return is required.
-         *
+         * @required
          * @return static
-         *
          */
         public function withMailer(MailerInterface $mailer)
         {
-            return new static($mailer);
+            $new = clone $this;
+            $new->mailer = $mailer;
+
+            return $new;
         }
 
         // ...
@@ -327,31 +322,6 @@ which allow the container to return the newly created service:
         $container->register('app.newsletter_manager', NewsletterManager::class)
             ->addMethodCall('withMailer', [new Reference('mailer')], true);
 
-This example is pretty simple, let's imagine that you have a simple service
-which use a `LoggerAwareTrait`::
-
-    class RandomService
-    {
-        use LoggerAwareTrait;
-    }
-
-    trait LoggerAwareTrait
-    {
-        private $logger;
-
-        /**
-         * @return static
-         */
-        public function withLogger(LoggerInterface $logger)
-        {
-            $new = clone $this;
-            $new->logger = $logger;
-
-            return $new;
-        }
-    }
-
-
 This approach is useful if you need to configure your service according to your needs, 
 so, what are the advantages?