Update entity.rst

Added "choice_translation_domain" and "translation_domain" documentation.

Author: merorafael

reference/forms/types/entity.rst

@@ -16,6 +16,8 @@ objects from the database.
 |             | - `choice_label`_                                                |
 |             | - `query_builder`_                                               |
 |             | - `em`_                                                          |
+|             | - `choice_translation_domain`_                                   |
+|             | - `translation_domain`_                                          |
 +-------------+------------------------------------------------------------------+
 | Overridden  | - `choices`_                                                     |
 | options     |                                                                  |
@@ -176,6 +178,26 @@ em
 If specified, this entity manager will be used to load the choices
 instead of the ``default`` entity manager.
 
+choice_translation_domain
+~~~~~~~~~~~~~
+
+.. versionadded:: 2.7
+    The ``choice_translation_domain`` option was introduced in Symfony 2.7.
+
+**type**: ``boolean``
+
+This option determines whether the translation of the data obtained will be informed domain ``translation_domain``.
+
+translation_domain
+~~~~~~~~~~~~~
+
+.. versionadded:: 2.7
+    The ``translation_domain`` option was introduced in Symfony 2.7.
+
+**type**: ``string``
+
+If specified, use translations of informed domain(e.g. ``AcmeStoreBundle`` to ``Acme\StoreBundle\Resources\translation`` files).
+
 
 Overridden Options
 ------------------