bug symfony#6679 Invalid PHP return statement (JohnnyEvo)

This PR was submitted for the 3.1 branch but it was merged into the 2.7 branch instead (closes symfony#6679).

Discussion
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Invalid PHP return statement

Add ';' to end return statement

Commits
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70ab2fe Invalid PHP return statement

Author: wouterj

reference/forms/types/choice.rst

@@ -107,7 +107,7 @@ method::
         },
         'group_by' => function($category, $key, $index) {
             // randomly assign things into 2 groups
-            return rand(0, 1) == 1 ? 'Group A' : 'Group B'
+            return rand(0, 1) == 1 ? 'Group A' : 'Group B';
         },
         'preferred_choices' => function($category, $key, $index) {
             return $category->getName() == 'Cat2' || $category->getName() == 'Cat3';