minor #7823 Mentioned that form related services can now be private (javiereguiluz)

This PR was squashed before being merged into the master branch (closes #7823).

Discussion
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Mentioned that form related services can now be private

This fixes #7687.

Commits
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d7fd0cb Mentioned that form related services can now be private

Author: javiereguiluz

form/create_custom_field_type.rst

@@ -339,6 +339,10 @@ the ``genders`` parameter value as the first argument to its to-be-created
     Make sure the services file is being imported. See :ref:`service-container-imports-directive`
     for details.
 
+.. versionadded:: 3.3
+    Prior to Symfony 3.3, you needed to define form type services as ``public``.
+    Starting from Symfony 3.3, you can also define them as ``private``.
+
 First, add a ``__construct`` method to ``GenderType``, which receives the gender
 configuration::
 

form/create_form_type_extension.rst

@@ -131,6 +131,10 @@ The ``extended_type`` key of the tag is the type of field that this extension sh
 be applied to. In your case, as you want to extend the ``Symfony\Component\Form\Extension\Core\Type\FileType``
 field type, you will use that as the ``extended_type``.
 
+.. versionadded:: 3.3
+    Prior to Symfony 3.3, you needed to define type extension services as ``public``.
+    Starting from Symfony 3.3, you can also define them as ``private``.
+
 .. tip::
 
     There is an optional tag attribute called ``priority``, which 

form/data_transformers.rst

@@ -334,11 +334,16 @@ Define the form type as a service in your configuration files.
             )
             ->addTag('form.type')
         ;
+
 .. tip::
 
     For more information about defining form types as services, read
     :doc:`register your form type as a service </form/form_dependencies>`.
 
+.. versionadded:: 3.3
+    Prior to Symfony 3.3, you needed to define form type services as ``public``.
+    Starting from Symfony 3.3, you can also define them as ``private``.
+
 Now, you can easily use your ``TaskType``::
 
     // e.g. in a controller somewhere

form/dynamic_form_modification.rst

@@ -370,6 +370,10 @@ you need to register it as a service and tag it with :ref:`form.type <dic-tags-f
 
         $container->setDefinition('app.form.friend_message', $definition);
 
+.. versionadded:: 3.3
+    Prior to Symfony 3.3, you needed to define form type services as ``public``.
+    Starting from Symfony 3.3, you can also define them as ``private``.
+
 In a controller that extends the :class:`Symfony\\Bundle\\FrameworkBundle\\Controller\\Controller`
 class, you can simply call::
 

form/form_dependencies.rst

@@ -136,6 +136,10 @@ Next, register this as a service and tag it with ``form.type``:
             ->addTag('form.type')
         ;
 
+.. versionadded:: 3.3
+    Prior to Symfony 3.3, you needed to define form type services as ``public``.
+    Starting from Symfony 3.3, you can also define them as ``private``.
+
 That's it! Your controller - where you create the form - doesn't need to change
 at all: Symfony is smart enough to load the ``TaskType`` from the container.
 

form/type_guesser.rst

@@ -217,6 +217,10 @@ creating a service and tagging it as ``form.type_guesser``:
             ->addTag('form.type_guesser')
         ;
 
+.. versionadded:: 3.3
+    Prior to Symfony 3.3, you needed to define type guesser services as ``public``.
+    Starting from Symfony 3.3, you can also define them as ``private``.
+
 .. sidebar:: Registering a Type Guesser in the Component
 
     If you're using the Form component standalone in your PHP project, use