minor #32044 [Validator] Fix GroupSequenceProvider annotation (enumag)

This PR was squashed before being merged into the 3.4 branch (closes #32044).

Discussion
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[Validator] Fix GroupSequenceProvider annotation

| Q             | A
| ------------- | ---
| Branch?       | 3.4
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |

The possibility was added in https://github.com/symfony/symfony/pull/19982, just forgot to fix this annotation back then.

Commits
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bf6d2532de [Validator] Fix GroupSequenceProvider annotation

src/Symfony/Component/Validator/Constraints/GroupSequence.php

@@ -57,7 +57,7 @@ class GroupSequence
     /**
      * The groups in the sequence.
      *
-     * @var string[]|array[]|GroupSequence[]
+     * @var string[]|string[][]|GroupSequence[]
      */
     public $groups;
 

src/Symfony/Component/Validator/GroupSequenceProviderInterface.php

@@ -22,7 +22,7 @@ interface GroupSequenceProviderInterface
      * Returns which validation groups should be used for a certain state
      * of the object.
      *
-     * @return string[]|GroupSequence An array of validation groups
+     * @return string[]|string[][]|GroupSequence An array of validation groups
      */
     public function getGroupSequence();
 }