chore: Add missing semicolon

Author: TheKhanj

components/dependency_injection.rst

@@ -300,6 +300,7 @@ config files:
             $services = $container->services();
             $services->set('mailer', 'Mailer')
                 ->args(['%mailer.transport%'])
+            ;
 
             $services->set('mailer', 'Mailer')
                 // the param() method was introduced in Symfony 5.2.