merged branch richsage/voterinterface-docblock-type (PR #8117)

This PR was submitted for the master branch but it was merged into the 2.1 branch instead (closes #8117).

Discussion
----------

[Security] Added type of return value in VoterInterface.

| Q             | A
| ------------- | ---
| Fixed tickets | none
| License       | MIT

Simple addition of the return type for the `supportsClass` method, as per the `supportsAttribute` method doc in the interface.

Commits
-------

c176d1e [Security] Added type of return value in VoterInterface.

src/Symfony/Component/Security/Core/Authorization/Voter/VoterInterface.php

@@ -38,7 +38,7 @@ interface VoterInterface
      *
      * @param string $class A class name
      *
-     * @return true if this Voter can process the class
+     * @return Boolean true if this Voter can process the class
      */
     public function supportsClass($class);