Fix Pong.hs to use contains instead of ix
Fix Pong.hs to use contains instead of ix

timjb/lens,cdepillabout/lens,Icelandjack/lens,hvr/lens,danidiaz/lens,Fuuzetsu/lens,cchalmers/lens,ddssff/lens,omefire/lens,hvr/lens,rpglover64/lens,Gabriel439/lens