split the Validation chapter

Author: xabbuh

bundles/override.rst

@@ -127,9 +127,9 @@ combines them into one validation metadata tree. This means you are able to
 add new constraints to a property, but you cannot override them.
 
 To override this, the 3rd party bundle needs to have configuration for
-:ref:`validation groups <book-validation-validation-groups>`. For instance,
-the FOSUserBundle has this configuration. To create your own validation, add
-the constraints to a new validation group:
+:doc:`validation groups </validation/groups>`. For instance, the FOSUserBundle
+has this configuration. To create your own validation, add the constraints
+to a new validation group:
 
 .. configuration-block::
 

forms.rst

@@ -467,7 +467,7 @@ Validation is a very powerful feature of Symfony and has its own
 Validation Groups
 ~~~~~~~~~~~~~~~~~
 
-If your object takes advantage of :ref:`validation groups <book-validation-validation-groups>`,
+If your object takes advantage of :doc:`validation groups </validation/groups>`,
 you'll need to specify which validation group(s) your form should use::
 
     $form = $this->createFormBuilder($users, array(
@@ -595,7 +595,7 @@ of the entity as well you have to adjust the option as follows::
     }
 
 You can find more information about how the validation groups and the default constraints
-work in the book section about :ref:`validation groups <book-validation-validation-groups>`.
+work in the book section about :doc:`validation groups </validation/groups>`.
 
 .. index::
    single: Forms; Validation groups based on clicked button
@@ -1899,6 +1899,8 @@ an array.
     a better choice, since it returns the data (usually an object) after
     it's been transformed by the Form component.
 
+.. _booking-validation-forms:
+
 Adding Validation
 ~~~~~~~~~~~~~~~~~
 
@@ -1915,7 +1917,7 @@ simple array of your submitted data, how can you add constraints to the data of
 your form?
 
 The answer is to setup the constraints yourself, and attach them to the individual
-fields. The overall approach is covered a bit more in the :ref:`validation chapter <book-validation-raw-values>`,
+fields. The overall approach is covered a bit more in the :doc:`validation chapter </validation/raw_values>`,
 but here's a short example:
 
 .. code-block:: php