add versioadded, codereview fixes

henry2778 · henry2778 · commit 227c9a13afa7 · 2021-03-21T22:49:44.000+02:00
diff --git a/reference/constraints/Unique.rst b/reference/constraints/Unique.rst
@@ -109,8 +109,8 @@ Options
 
 .. include:: /reference/constraints/_groups-option.rst.inc
 
-``message``
-~~~~~~~~~~~
+message
+~~~~~~~
 
 **type**: ``string`` **default**: ``This collection should contain only unique elements.``
 
@@ -130,13 +130,17 @@ Parameter                      Description
 
 **type**: a `PHP callable`_ **default**: ``null``
 
+.. versionadded:: 5.3
+
+    The ``normalizer`` option was introduced in Symfony 5.3.
+
 This option allows to define the PHP callable applied to each element of the given collection before
 checking if the collection is valid.
 
 For example, you may want to pass the ``'trim'`` string to apply the
 :phpfunction:`trim` PHP function to each element of the collection in order to ignore leading and trailing
 whitespace during validation.
 
-.. _`PHP callable`: https://www.php.net/callable
-
 .. include:: /reference/constraints/_payload-option.rst.inc
+
+.. _`PHP callable`: https://www.php.net/callable
