minor #20319 [Form] Documenting choice_lazy option (yceruto)

This PR was merged into the 7.2 branch.

Discussion
----------

[Form] Documenting ``choice_lazy`` option

Closes #20311
Code PR
* symfony/symfony#52503

Commits
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e55e7cd documenting choice_lazy option

Author: javiereguiluz

reference/forms/types/choice.rst

@@ -178,6 +178,8 @@ correct types will be assigned to the model.
 
 .. include:: /reference/forms/types/options/choice_loader.rst.inc
 
+.. include:: /reference/forms/types/options/choice_lazy.rst.inc
+
 .. include:: /reference/forms/types/options/choice_name.rst.inc
 
 .. include:: /reference/forms/types/options/choice_translation_domain_enabled.rst.inc

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

@@ -0,0 +1,31 @@
+``choice_lazy``
+~~~~~~~~~~~~~~~
+
+**type**: ``boolean`` **default**: ``false``
+
+The ``choice_lazy`` option is especially useful when dealing with a large set of
+choices, where loading all of them at once could lead to performance issues or
+significant delays::
+
+    use App\Entity\User;
+    use Symfony\Bridge\Doctrine\Form\Type\EntityType;
+
+    $builder->add('user', EntityType::class, [
+        'class' => User::class,
+        'choice_lazy' => true,
+    ]);
+
+When set to ``true``, and used in combination with the ``choice_loader`` option,
+the form will only load and render the choices that are preset as default values
+or submitted. This allows you to defer loading the full list of choices and can
+improve the performance of your form.
+
+.. caution::
+
+    Please note that when using ``choice_lazy``, you are responsible for providing
+    the user interface to select choices, typically through a JavaScript plugin that
+    can handle the dynamic loading of choices.
+
+.. versionadded:: 7.2
+
+    The ``choice_lazy`` option was introduced in Symfony 7.2.