minor #38995 [Security] Fix docblock (derrabus)

This PR was merged into the 4.4 branch.

Discussion
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[Security] Fix docblock

| Q             | A
| ------------- | ---
| Branch?       | 4.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Tickets       | N/A
| License       | MIT
| Doc PR        | N/A

Commits
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60e506835a [Security] Fix docblock.

src/Symfony/Component/Security/Core/Authentication/Token/Storage/TokenStorageInterface.php

@@ -30,7 +30,7 @@ interface TokenStorageInterface
     /**
      * Sets the authentication token.
      *
-     * @param TokenInterface $token A TokenInterface token, or null if no further authentication information should be stored
+     * @param TokenInterface|null $token A TokenInterface token, or null if no further authentication information should be stored
      */
     public function setToken(TokenInterface $token = null);
 }