minor #3506 Nykopol overriden options (weaverryan)

This PR was merged into the 2.3 branch.

Discussion
----------

Nykopol overriden options

See #3417 - this is just a rebase to continue it :)

| Q             | A
| ------------- | ---
| Doc fix?      | no
| New docs?     | yes
| Applies to    | 2.3
| Fixed tickets | #3412

Thanks!

Commits
-------

e574e97 Removing an extra line thanks to @xabbuh
4f6cb9d Some additional tweaks and probably some merge conflict fixes
362c8b4 document overriden options of choice field
70feefd document overriden options of checkbox
c62cd13 correct overriden option of button and add checkbox overriden option
ab4aafe correct overriden option of button and add checkbox overriden option

Author: weaverryan

reference/forms/types/button.rst

@@ -18,7 +18,7 @@ A simple, non-responsive button.
 |                      | - `label_attr`_                                                      |
 |                      | - `translation_domain`_                                              |
 +----------------------+----------------------------------------------------------------------+
-| Overridden Options   | - `auto_initialize`                                                  |
+| Overridden options   | - `auto_initialize`_                                                 |
 +----------------------+----------------------------------------------------------------------+
 | Parent type          | none                                                                 |
 +----------------------+----------------------------------------------------------------------+

reference/forms/types/checkbox.rst

@@ -13,9 +13,11 @@ if the box is unchecked, the value will be set to false.
 +-------------+------------------------------------------------------------------------+
 | Options     | - `value`_                                                             |
 +-------------+------------------------------------------------------------------------+
+| Overridden  | - `empty_data`_                                                        |
+| options     | - `compound`_                                                          |
++-------------+------------------------------------------------------------------------+
 | Inherited   | - `data`_                                                              |
-| options     | - `empty_data`_                                                        |
-|             | - `required`_                                                          |
+| options     | - `required`_                                                          |
 |             | - `label`_                                                             |
 |             | - `label_attr`_                                                        |
 |             | - `read_only`_                                                         |
@@ -44,6 +46,13 @@ Field Options
 
 .. include:: /reference/forms/types/options/value.rst.inc
 
+Overridden options
+------------------
+
+.. include:: /reference/forms/types/options/checkbox_empty_data.rst.inc
+
+.. include:: /reference/forms/types/options/checkbox_compound.rst.inc
+
 Inherited options
 -----------------
 

reference/forms/types/choice.rst

@@ -20,18 +20,20 @@ option.
 |             | - `preferred_choices`_                                                       |
 |             | - `empty_value`_                                                             |
 +-------------+------------------------------------------------------------------------------+
+| Overridden  | - `empty_data`_                                                              |
+| options     | - `compound`_                                                                |
+|             | - `error_bubbling`_                                                          |
++-------------+------------------------------------------------------------------------------+
 | Inherited   | - `required`_                                                                |
 | options     | - `label`_                                                                   |
 |             | - `label_attr`_                                                              |
 |             | - `data`_                                                                    |
 |             | - `read_only`_                                                               |
 |             | - `disabled`_                                                                |
-|             | - `error_bubbling`_                                                          |
 |             | - `error_mapping`_                                                           |
 |             | - `mapped`_                                                                  |
 |             | - `inherit_data`_                                                            |
 |             | - `by_reference`_                                                            |
-|             | - `empty_data`_                                                              |
 +-------------+------------------------------------------------------------------------------+
 | Parent type | :doc:`form </reference/forms/types/form>`                                    |
 +-------------+------------------------------------------------------------------------------+
@@ -109,6 +111,27 @@ can be created to supply the choices.
 
 .. include:: /reference/forms/types/options/empty_value.rst.inc
 
+Overridden options
+------------------
+
+.. include:: /reference/forms/types/options/empty_data.rst.inc
+
+compound
+~~~~~~~~
+
+**type**: ``boolean`` **default**: same value as ``expanded`` option
+
+This option specifies if a form is compound. The value is by default 
+overriden by the value of the ``expanded`` option.
+
+error_bubbling
+~~~~~~~~~~~~~~
+
+**type**: ``boolean`` **default**: ``false``
+
+Set that error on this field must be attached to the field instead of 
+the parent field (the form in most cases).
+
 Inherited options
 -----------------
 
@@ -126,14 +149,10 @@ These options inherit from the :doc:`form </reference/forms/types/form>` type:
 
 .. include:: /reference/forms/types/options/disabled.rst.inc
 
-.. include:: /reference/forms/types/options/error_bubbling.rst.inc
-
 .. include:: /reference/forms/types/options/error_mapping.rst.inc
 
 .. include:: /reference/forms/types/options/mapped.rst.inc
 
 .. include:: /reference/forms/types/options/inherit_data.rst.inc
 
 .. include:: /reference/forms/types/options/by_reference.rst.inc
-
-.. include:: /reference/forms/types/options/empty_data.rst.inc

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

@@ -0,0 +1,8 @@
+compound
+~~~~~~~~
+
+**type**: ``boolean`` **default**: ``false``
+
+This option specifies if a form is compound. As it's not the
+case for checkbox, by fefault the value is overriden with
+``false`` value.

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

@@ -0,0 +1,9 @@
+empty_data
+~~~~~~~~~~
+
+**type**: ``string`` **default**: ``mixed``
+
+This option determines what value the field will return when the ``empty_value``
+choice is selected.
+In checkbox, the value of ``empty_data`` is overriden by the value returned by
+the data transformer (see :doc:`/cookbook/form/data_transformers.rst`).