Updated all the README files

Author: javiereguiluz

README.md

@@ -1,15 +1,16 @@
 Serializer Component
 ====================
 
-With the Serializer component it's possible to handle serializing data structures,
-including object graphs, into array structures or other formats like XML and JSON.
-It can also handle deserializing XML and JSON back to object graphs.
+With the Serializer component it's possible to handle serializing data
+structures, including object graphs, into array structures or other formats like
+XML and JSON. It can also handle deserializing XML and JSON back to object
+graphs.
 
 Resources
 ---------
 
-You can run the unit tests with the following command:
-
-    $ cd path/to/Symfony/Component/Serializer/
-    $ composer install
-    $ phpunit
+  * [Documentation](https://symfony.com/doc/current/components/serializer.html)
+  * [Contributing](https://symfony.com/doc/current/contributing/index.html)
+  * [Report issues](https://github.com/symfony/symfony/issues) and
+    [send Pull Requests](https://github.com/symfony/symfony/pulls)
+    in the [main Symfony repository](https://github.com/symfony/symfony)