Merge branch '3.4' into 4.0

* 3.4:
  Update service_container.rst
  [Validation]  Added internal link

Author: javiereguiluz

service_container.rst

@@ -972,7 +972,7 @@ admin email. In this case, each needs to have a unique service id:
                     <argument>contact@example.com</argument>
                 </service>
 
-                <alias id="App\Updates\SiteUpdateManager" service="site_update_manager.superadmin" />
+                <service id="App\Updates\SiteUpdateManager" alias="site_update_manager.superadmin" />
             </services>
         </container>
 

validation.rst

@@ -482,7 +482,7 @@ options can be specified in this way.
 This is purely meant to make the configuration of the most common option of
 a constraint shorter and quicker.
 
-If you're ever unsure of how to specify an option, either check the API documentation
+If you're ever unsure of how to specify an option, either check :namespace:`Symfony\\Component\\Validator\\Constraints`
 for the constraint or play it safe by always passing in an array of options
 (the first method shown above).