docs(css): enable momentum scrolling for iOS
docs(css): enable momentum scrolling for iOS

https://developer.mozilla.org/en-US/docs/Web/CSS/-webkit-overflow-scrolling

All other mobile and desktop platforms with built-in momentum scrolling
enable it by default. iOS requires an explicit CSS rule.

benlesh/RxJS,ReactiveX/RxJS,jayphelps/rxjs,jayphelps/rxjs,ReactiveX/rxjs,SangKa/RxJS-Docs-CN,RxJS-CN/RxJS-Docs-CN,IgorMinar/RxJS,benlesh/RxJS,trxcllnt/RxJS,RxJS-CN/RxJS-Docs-CN,martinsik/rxjs,ReactiveX/RxJS,martinsik/rxjs,martinsik/rxjs,RxJS-CN/RxJS-Docs-CN,martinsik/rxjs,RxJS-CN/RxJS-Docs-CN,ReactiveX/RxJS,SangKa/RxJS-Docs-CN,jayphelps/rxjs,SangKa/RxJS-Docs-CN,benlesh/RxJS,trxcllnt/RxJS,Brocco/RxJS,benlesh/RxJS,trxcllnt/RxJS,SangKa/RxJS-Docs-CN,IgorMinar/RxJS,ReactiveX/rxjs,trxcllnt/RxJS,Brocco/RxJS,Brocco/RxJS,ReactiveX/RxJS,kwonoj/RxJS,kwonoj/RxJS,Brocco/RxJS,ReactiveX/rxjs,ReactiveX/rxjs,jayphelps/rxjs,kwonoj/RxJS,kwonoj/RxJS,jayphelps/rxjs