fix a typo in a link URL: s/Sbject/Subject/
fix a typo in a link URL: s/Sbject/Subject/

ReactiveX/reactivex.github.io,phajduk/reactivex.github.io,BattleShipPark/reactivex.github.io,ReactiveX/reactivex.github.io,ReactiveX/reactivex.github.io,BattleShipPark/reactivex.github.io,BattleShipPark/reactivex.github.io,phajduk/reactivex.github.io,phajduk/reactivex.github.io