minor #6457 Fixed an array notation in comment (serializer.rst) (iltar)

This PR was merged into the 2.7 branch.

Discussion
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Fixed an array notation in comment (serializer.rst)

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | all
| Fixed tickets | #6422 (comment)

Fixed against the right branch, reverted from other pr. The other pr is against 2.3, this was not in 2.3 yet.

Commits
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78ddfef Fixed an array notation in comment (serializer.rst)

Author: xabbuh

components/serializer.rst

@@ -300,7 +300,7 @@ You are now able to serialize only attributes in the groups you want::
     $serializer = new Serializer(array($normalizer));
 
     $data = $serializer->normalize($obj, null, array('groups' => array('group1')));
-    // $data = ['foo' => 'foo'];
+    // $data = array('foo' => 'foo');
 
     $obj2 = $serializer->denormalize(
         array('foo' => 'foo', 'bar' => 'bar'),