bug #14602 Fix wrong key name in FormType options (matthieudanet)

This PR was merged into the 5.1 branch.

Discussion
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Fix wrong key name in FormType options

Fix wrong key name in FormType options

Commits
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0723043 Fix wrong key name

Author: OskarStark

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

@@ -49,7 +49,7 @@ If an array, the keys of the ``choices`` array must be used as keys::
 
         // ...
         $builder->add('choices', ChoiceType::class, [
-            'choice_label' => ChoiceList::attr($this, function (?Category $category) {
+            'choice_attr' => ChoiceList::attr($this, function (?Category $category) {
                 return $category ? ['data-uuid' => $category->getUuid()] : [];
             }),
         ]);