[Generator] correct createClassNameDetails doc

[ayyoub-afwallah]

you can use the following test cases in GeneratorTest for a quick verification.

   yield 'example_1' => [
        'Foo\\Admin',
        'Controller',
        'Controller',
        'App\Controller\Foo\AdminController',
        'Foo\AdminController',
    ];`

    yield 'example_2' => [
        'Cool',
        'Security\Voter',
        'Voter',
        'App\Security\Voter\CoolVoter',
        'CoolVoter',
    ];`

[jrushlow]

Thank you @ayyoub-afwallah