[FrameworkBundle] Update serializer configuration reference

Author: dunglas

reference/configuration/framework.rst

@@ -92,7 +92,7 @@ Configuration
 * `validation`_
     * :ref:`enabled <reference-validation-enabled>`
     * :ref:`cache <reference-validation-cache>`
-    * `enable_annotations`_
+    * :ref:`enable_annotations <reference-validation-enable_annotations>`
     * `translation_domain`_
     * `strict_email`_
     * `api`_
@@ -102,6 +102,8 @@ Configuration
     * `debug`_
 * `serializer`_
     * :ref:`enabled <reference-serializer-enabled>`
+    * :ref:`cache <reference-serializer-cache>`
+    * :ref:`enable_annotations <reference-serializer-enable_annotations>`
 
 secret
 ~~~~~~
@@ -681,6 +683,21 @@ Whether to enable the ``serializer`` service or not in the service container.
 
 For more details, see :doc:`/cookbook/serializer`.
 
+cache
+.....
+
+**type**: ``string``
+
+The service that is used to persist class metadata in a cache. The service
+has to implement the :class:`Doctrine\\Common\\Cache\\Cache` interface.
+
+enable_annotations
+..................
+
+**type**: ``boolean`` **default**: ``false``
+
+If this option is enabled, serialization groups can be defined using annotations.
+
 templating
 ~~~~~~~~~~
 
@@ -1567,6 +1584,8 @@ Full Default Configuration
             # serializer configuration
             serializer:
                enabled: false
+               cache:                ~
+               enable_annotations:   false
 
             # templating configuration
             templating: