[Translation] Update the contents about Doctrine entity translation

Author: javiereguiluz

translation.rst

@@ -562,16 +562,22 @@ if you're generating translations with specialized programs or teams.
                 ;
             };
 
-.. note::
-
-    You can also store translations in a database; it can be handled by
-    Doctrine through the `Translatable Extension`_ or the `Translatable Behavior`_
-    (PHP 5.4+). For more information, see the documentation for these libraries.
-
-    For any other storage, you need to provide a custom class implementing the
-    :class:`Symfony\\Component\\Translation\\Loader\\LoaderInterface`
-    interface. See the :ref:`dic-tags-translation-loader` tag for more
-    information.
+Translations of Doctrine Entities
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Unlike the contents of templates, it's not practical to translate the contents
+stored in Doctrine Entities using translation catalogs. Instead, use the
+Doctrine `Translatable Extension`_ or the `Translatable Behavior`_. For more
+information, see the documentation for these libraries.
+
+Custom Translation Resources
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+If your translations use a format not supported by Symfony or you store them
+in not using Doctrine entities, you need to provide a custom class implementing
+the :class:`Symfony\\Component\\Translation\\Loader\\LoaderInterface`
+interface. See the :ref:`dic-tags-translation-loader` tag for more
+information.
 
 .. _translation-providers: