Fix PHPdoc in lib/private

lib/private/app.php

lib/private/cache/file.php

lib/private/connector/sabre/directory.php

lib/private/filechunking.php

lib/private/files/storage/common.php

lib/private/files/storage/mappedlocal.php

lib/private/image.php

lib/private/request.php

lib/private/route/route.php

lib/private/route/router.php

lib/private/urlgenerator.php