minor #14103 Remove manual enabling of validation and validator annotations (l-vo)

This PR was merged into the 4.4 branch.

Discussion
----------

Remove manual enabling of validation and validator annotations

According to [framework validation configuration](https://github.com/symfony/symfony/blob/88bf7211a9b648dfba519455f7f25f34d693df06/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php#L801), since Symfony standard edition doesn't exist anymore for 4.4:

- Enabling validation is not needed anymore as long as `symfony/validator` is enabled
- Enabling validation annotations is not needed anymore as long as `doctrine/annotations` is enabled

Commits
-------

af5401a Remove manual enabling of validation and validator annotations

Author: javiereguiluz

validation.rst

@@ -212,77 +212,7 @@ Inside the template, you can output the list of errors exactly as needed:
 Configuration
 -------------
 
-Before using the Symfony validator, make sure it's enabled in the main config
-file:
-
-.. configuration-block::
-
-    .. code-block:: yaml
-
-        # config/packages/framework.yaml
-        framework:
-            validation: { enabled: true }
-
-    .. code-block:: xml
-
-        <!-- config/packages/framework.xml -->
-        <?xml version="1.0" encoding="UTF-8" ?>
-        <container xmlns="http://symfony.com/schema/dic/services"
-            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-            xmlns:framework="http://symfony.com/schema/dic/symfony"
-            xsi:schemaLocation="http://symfony.com/schema/dic/services
-                https://symfony.com/schema/dic/services/services-1.0.xsd
-                http://symfony.com/schema/dic/symfony https://symfony.com/schema/dic/symfony/symfony-1.0.xsd">
-
-            <framework:config>
-                <framework:validation enabled="true"/>
-            </framework:config>
-        </container>
-
-    .. code-block:: php
-
-        // config/packages/framework.php
-        $container->loadFromExtension('framework', [
-            'validation' => [
-                'enabled' => true,
-            ],
-        ]);
-
-Besides, if you plan to use annotations to configure validation, replace the
-previous configuration by the following:
-
-.. configuration-block::
-
-    .. code-block:: yaml
-
-        # config/packages/framework.yaml
-        framework:
-            validation: { enable_annotations: true }
-
-    .. code-block:: xml
-
-        <!-- config/packages/framework.xml -->
-        <?xml version="1.0" encoding="UTF-8" ?>
-        <container xmlns="http://symfony.com/schema/dic/services"
-            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-            xmlns:framework="http://symfony.com/schema/dic/symfony"
-            xsi:schemaLocation="http://symfony.com/schema/dic/services
-                https://symfony.com/schema/dic/services/services-1.0.xsd
-                http://symfony.com/schema/dic/symfony https://symfony.com/schema/dic/symfony/symfony-1.0.xsd">
-
-            <framework:config>
-                <framework:validation enable-annotations="true"/>
-            </framework:config>
-        </container>
-
-    .. code-block:: php
-
-        // config/packages/framework.php
-        $container->loadFromExtension('framework', [
-            'validation' => [
-                'enable_annotations' => true,
-            ],
-        ]);
+In the previous Symfony versions, enabling the validator in configuration was a requirement. It's not the case anymore, the validation is enabled by default as long as the Validator component is installed. In the same way, annotations are enabled by default if ``doctrine/annotations`` is installed.
 
 .. tip::