Update console.rst

Parent constructor call is required when using auto-wired services in a command constructor, without it you will receive the error:

```
There are no commands defined in the "app" namespace.
```

Author: vekien

console.rst

@@ -184,6 +184,8 @@ as a service, you can use normal dependency injection. Imagine you have a
         public function __construct(UserManager $userManager)
         {
             $this->userManager = $userManager;
+            
+            parent::__construct();
         }
 
         // ...