Added missing comment on IDownloadProvider return
Added missing comment on IDownloadProvider return

AlexCatarino/Lean,jameschch/Lean,QuantConnect/Lean,StefanoRaggi/Lean,AlexCatarino/Lean,QuantConnect/Lean,jameschch/Lean,QuantConnect/Lean,StefanoRaggi/Lean,AlexCatarino/Lean,StefanoRaggi/Lean,StefanoRaggi/Lean,QuantConnect/Lean,AlexCatarino/Lean,jameschch/Lean,JKarathiya/Lean,StefanoRaggi/Lean,jameschch/Lean,JKarathiya/Lean,JKarathiya/Lean,jameschch/Lean,JKarathiya/Lean