[Serializer] Fixes in group support

Author: dunglas

components/serializer.rst

@@ -146,10 +146,10 @@ Attributes Groups
     The support of serialization and deserialization groups was introduced
     in Symfony 2.7.
 
-Sometimes, you want to serialize different set of attributes from your
+Sometimes, you want to serialize different sets of attributes from your
 entities. Groups are a handy way to achieve this need.
 
-Assume you have the following object plain-old-PHP object::
+Assume you have the following plain-old-PHP object::
 
     namespace Acme;
 
@@ -217,8 +217,10 @@ Then, create your groups definition:
 
         <?xml version="1.0" ?>
         <serializer xmlns="http://symfony.com/schema/dic/serializer-mapping"
-                            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-                            xsi:schemaLocation="http://symfony.com/schema/dic/serializer-mapping http://symfony.com/schema/dic/serializer-mapping/serializer-mapping-1.0.xsd">
+            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+            xsi:schemaLocation="http://symfony.com/schema/dic/serializer-mapping
+                http://symfony.com/schema/dic/serializer-mapping/serializer-mapping-1.0.xsd"
+        >
             <class name="Acme\MyObj">
                 <attribute name="foo">
                     <group>group1</group>
@@ -234,13 +236,13 @@ Then, create your groups definition:
 You are now able to serialize only attributes in the groups you want::
 
     use Symfony\Component\Serializer\Serializer;
-    use Symfony\Component\Serializer\Normalizer\GetSetMethodNormalizer;
+    use Symfony\Component\Serializer\Normalizer\ObjectNormalizer;
 
     $obj = new MyObj();
     $obj->foo = 'foo';
     $obj->bar = 'bar';
 
-    $normalizer = new PropertyNormalizer($classMetadataFactory);
+    $normalizer = new ObjectNormalizer($classMetadataFactory);
     $serializer = new Serializer(array($normalizer));
 
     $data = $serializer->normalize($obj, null, array('groups' => array('group1')));