test(dtslint): add dtslint test for never observable static function (#4093) (#4449)
test(dtslint): add dtslint test for never observable static function (#4093) (#4449)


trxcllnt/RxJS,martinsik/rxjs,Brocco/RxJS,Brocco/RxJS,ReactiveX/rxjs,Brocco/RxJS,benlesh/RxJS,kwonoj/RxJS,Brocco/RxJS,trxcllnt/RxJS,kwonoj/RxJS,martinsik/rxjs,kwonoj/RxJS,trxcllnt/RxJS,benlesh/RxJS,ReactiveX/rxjs,ReactiveX/rxjs,benlesh/RxJS,ReactiveX/RxJS,martinsik/rxjs,ReactiveX/RxJS,ReactiveX/RxJS,martinsik/rxjs,benlesh/RxJS,kwonoj/RxJS,ReactiveX/RxJS,ReactiveX/rxjs,trxcllnt/RxJS