feature #21002 [Form] Added options for separate date/time labels in …

…DateTimeType. (mktcode)

This PR was squashed before being merged into the 4.2-dev branch (closes #21002).

Discussion
----------

[Form] Added options for separate date/time labels in DateTimeType.

If your render date and time separately you need options for each label.

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| License       | MIT

Let's say you have the following form field:

```
$builder
    ->add('start', DateTimeType::class, [
        'date_widget' => 'single_text',
        ...
    ])
    ...
```
Then you can render the date and time widgets/rows/etc. separately:

```
<div>{{ form_row(form.start.date) }}</div>
<div>{{ form_row(form.start.time) }}</div>
```
But you can't provide labels for each, so what is displayed is just the uppercased field name ("Date" and "Time").

This PR adds 'date_label' and 'time_label' options, so you can do:
```
$builder
    ->add('start', DateTimeType::class, [
        'date_widget' => 'single_text',
        'date_label' => 'The Start Date',
        'time_label' => 'The Start Time',
        ...
    ])
    ...
```

Commits
-------

df19155 [Form] Added options for separate date/time labels in DateTimeType.

src/Symfony/Component/Form/Extension/Core/Type/DateTimeType.php

@@ -137,10 +137,18 @@ public function buildForm(FormBuilderInterface $builder, array $options)
                 $dateOptions['widget'] = $options['date_widget'];
             }
 
+            if (null !== $options['date_label']) {
+                $dateOptions['label'] = $options['date_label'];
+            }
+
             if (null !== $options['time_widget']) {
                 $timeOptions['widget'] = $options['time_widget'];
             }
 
+            if (null !== $options['time_label']) {
+                $timeOptions['label'] = $options['time_label'];
+            }
+
             if (null !== $options['date_format']) {
                 $dateOptions['format'] = $options['date_format'];
             }
@@ -235,6 +243,8 @@ public function configureOptions(OptionsResolver $resolver)
             // this option.
             'data_class' => null,
             'compound' => $compound,
+            'date_label' => null,
+            'time_label' => null,
         ));
 
         // Don't add some defaults in order to preserve the defaults