minor #7824 Fixed the form types of the buttons in the Form reference (javiereguiluz)

This PR was squashed before being merged into the 2.8 branch (closes #7824).

Discussion
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Fixed the form types of the buttons in the Form reference

This fixes #6864.

Commits
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7239fb9 Fixed the form types of the buttons in the Form reference

Author: xabbuh

reference/forms/types/button.rst

@@ -31,7 +31,21 @@ The ``BaseType`` class is the parent class for both the ``button`` type
 and the :doc:`FormType </reference/forms/types/form>`, but it is not part
 of the form type tree (i.e. it cannot be used as a form type on its own).
 
-.. include:: /reference/forms/types/options/button_attr.rst.inc
+attr
+~~~~
+
+**type**: ``array`` **default**: ``array()``
+
+If you want to add extra attributes to the HTML representation of the button,
+you can use ``attr`` option. It's an associative array with HTML attribute
+as a key. This can be useful when you need to set a custom class for the button::
+
+    use Symfony\Component\Form\Extension\Core\Type\ButtonType;
+    // ...
+
+    $builder->add('save', ButtonType::class, array(
+        'attr' => array('class' => 'save'),
+    ));
 
 .. include:: /reference/forms/types/options/button_disabled.rst.inc
 

reference/forms/types/options/button_attr.rst.inc

@@ -26,7 +26,21 @@ A button that resets all fields to their original values.
 Inherited Options
 -----------------
 
-.. include:: /reference/forms/types/options/button_attr.rst.inc
+attr
+~~~~
+
+**type**: ``array`` **default**: ``array()``
+
+If you want to add extra attributes to the HTML representation of the button,
+you can use ``attr`` option. It's an associative array with HTML attribute
+as a key. This can be useful when you need to set a custom class for the button::
+
+    use Symfony\Component\Form\Extension\Core\Type\ResetType;
+    // ...
+
+    $builder->add('save', ResetType::class, array(
+        'attr' => array('class' => 'save'),
+    ));
 
 .. include:: /reference/forms/types/options/button_disabled.rst.inc
 

reference/forms/types/reset.rst

@@ -37,7 +37,21 @@ useful when :doc:`a form has multiple submit buttons </form/multiple_buttons>`::
 Inherited Options
 -----------------
 
-.. include:: /reference/forms/types/options/button_attr.rst.inc
+attr
+~~~~
+
+**type**: ``array`` **default**: ``array()``
+
+If you want to add extra attributes to the HTML representation of the button,
+you can use ``attr`` option. It's an associative array with HTML attribute
+as a key. This can be useful when you need to set a custom class for the button::
+
+    use Symfony\Component\Form\Extension\Core\Type\SubmitType;
+    // ...
+
+    $builder->add('save', SubmitType::class, array(
+        'attr' => array('class' => 'save'),
+    ));
 
 .. include:: /reference/forms/types/options/button_disabled.rst.inc