bundles - add reason why they are not recommended

Author: landsman

bundles.rst

@@ -6,7 +6,7 @@ The Bundle System
 .. caution::
 
     In Symfony versions prior to 4.0, it was recommended to organize your own
-    application code using bundles. This is no longer recommended and bundles
+    application code using bundles. This is `no longer recommended <https://symfony.com/doc/current/best_practices.html#don-t-create-any-bundle-to-organize-your-application-logic>`_ and bundles
     should only be used to share code and features between multiple applications.
 
 A bundle is similar to a plugin in other software, but even better. The core