minor #10389 Documented the new date_label and time_label options (javiereguiluz)

This PR was squashed before being merged into the master branch (closes #10389).

Discussion
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Documented the new date_label and time_label options

Fixes #10292.

Commits
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eee1eaa Documented the new date_label and time_label options

Author: javiereguiluz

reference/forms/types/datetime.rst

@@ -17,6 +17,7 @@ the data can be a ``DateTime`` object, a string, a timestamp or an array.
 +----------------------+-----------------------------------------------------------------------------+
 | Options              | - `choice_translation_domain`_                                              |
 |                      | - `date_format`_                                                            |
+|                      | - `date_label`_                                                             |
 |                      | - `date_widget`_                                                            |
 |                      | - `days`_                                                                   |
 |                      | - `placeholder`_                                                            |
@@ -28,6 +29,7 @@ the data can be a ``DateTime`` object, a string, a timestamp or an array.
 |                      | - `model_timezone`_                                                         |
 |                      | - `months`_                                                                 |
 |                      | - `seconds`_                                                                |
+|                      | - `time_label`_                                                             |
 |                      | - `time_widget`_                                                            |
 |                      | - `view_timezone`_                                                          |
 |                      | - `widget`_                                                                 |
@@ -67,6 +69,23 @@ Defines the ``format`` option that will be passed down to the date field.
 See the :ref:`DateType's format option <reference-forms-type-date-format>`
 for more details.
 
+date_label
+~~~~~~~~~~
+
+**type**: ``string`` | ``null`` **default**: The label is "guessed" from the field name
+
+.. versionadded:: 4.2
+    The ``date_label`` option was introduced in Symfony 4.2.
+
+Sets the label that will be used when rendering the date widget. Setting it to
+``false`` will suppress the label::
+
+    use Symfony\Component\Form\Extension\Core\Type\DateTimeType;
+
+    $builder->add('startDateTime', DateTimeType::class, array(
+        'date_label' => 'Starts On',
+    ));
+
 date_widget
 ~~~~~~~~~~~
 
@@ -144,6 +163,23 @@ this format.
 
 .. include:: /reference/forms/types/options/seconds.rst.inc
 
+time_label
+~~~~~~~~~~
+
+**type**: ``string`` | ``null`` **default**: The label is "guessed" from the field name
+
+.. versionadded:: 4.2
+    The ``time_label`` option was introduced in Symfony 4.2.
+
+Sets the label that will be used when rendering the time widget. Setting it to
+``false`` will suppress the label::
+
+    use Symfony\Component\Form\Extension\Core\Type\DateTimeType;
+
+    $builder->add('startDateTime', DateTimeType::class, array(
+        'time_label' => 'Starts On',
+    ));
+
 time_widget
 ~~~~~~~~~~~