Cleanup of PHPDoc return types

apps/files_sharing/lib/cache.php

apps/files_sharing/lib/controllers/sharecontroller.php

apps/files_sharing/lib/sharedstorage.php

apps/user_ldap/lib/access.php

apps/user_ldap/lib/wizard.php

apps/user_ldap/user_ldap.php

lib/private/app.php

lib/private/appconfig.php

lib/private/appframework/core/api.php

lib/private/files/cache/cache.php

lib/private/files/cache/wrapper/cachejail.php

lib/private/files/cache/wrapper/cachewrapper.php

lib/private/files/storage/common.php

lib/private/hook.php

lib/private/tags.php

lib/public/files/storage.php

lib/public/iappconfig.php

lib/public/itags.php

lib/public/share_backend.php