minor symfony#4949 Fixes for 2.3 branch (ifdattic)

This PR was merged into the 2.3 branch.

Discussion
----------

Fixes for 2.3 branch

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | 2.3
| Fixed tickets |

Commits
-------

e6ffd5d Add missing comma in array
da70836 Fix typos

Author: weaverryan

components/serializer.rst

@@ -139,7 +139,7 @@ of the ``Person`` class would be encoded in XML format::
     </person>
     EOF;
 
-    $person = $serializer->deserialize($data,'Acme\Person','xml');
+    $person = $serializer->deserialize($data, 'Acme\Person', 'xml');
 
 In this case, :method:`Symfony\\Component\\Serializer\\Serializer::deserialize`
 needs three parameters:

components/templating/introduction.rst

@@ -196,7 +196,7 @@ method is used.
 
     $templating = new DelegatingEngine(array(
         new PhpEngine(...),
-        new CustomEngine(...)
+        new CustomEngine(...),
     ));
 
 .. _Packagist: https://packagist.org/packages/symfony/templating