svtplay: show a better error message if we cant find video
svtplay: show a better error message if we cant find video

qnorsten/svtplay-dl,dalgr/svtplay-dl,spaam/svtplay-dl,dalgr/svtplay-dl,qnorsten/svtplay-dl,spaam/svtplay-dl,olof/svtplay-dl,selepo/svtplay-dl,olof/svtplay-dl,selepo/svtplay-dl