test(dtslint): add dtslint test for concat observable (#4093) (#4407)
test(dtslint): add dtslint test for concat observable (#4093) (#4407)


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