Fix ControllerBase stateService documentation

API page: https://api.drupal.org/api/drupal/core%21lib%21Drupal%21Core%21Controlle...

Enter a descriptive title (above) relating to abstract class ControllerBase, then describe the problem you have found:

protected $stateService is documented as @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface but it is actually @var \Drupal\Core\State\StateInterface.

Likewise, protected function state() is documented as @return \Drupal\Core\KeyValueStore\KeyValueStoreInterface but it actually should be @return \Drupal\Core\State\StateInterface.

Note the core 'state' service, which is stored in the $stateService instance variable and returned by the state() function, is documented in core.services.yml as:

  state:
    class: Drupal\Core\State\State
    arguments: ['@keyvalue', '@cache.bootstrap', '@lock']
    tags:
      - { name: needs_destruction }