Pass result of &prompt through &val.
Pass result of &prompt through &val.

Fixes rakudo/rakudo#1906.

rakudo/rakudo,tbrowder/rakudo,tony-o/rakudo,salortiz/rakudo,Gnouc/rakudo,labster/rakudo,MasterDuke17/rakudo,Gnouc/rakudo,nbrown/rakudo,MasterDuke17/rakudo,Gnouc/rakudo,labster/rakudo,tony-o/rakudo,labster/rakudo,labster/rakudo,tony-o/rakudo,tbrowder/rakudo,tony-o/rakudo,rakudo/rakudo,MasterDuke17/rakudo,softmoth/rakudo,tony-o/rakudo,nbrown/rakudo,tbrowder/rakudo,MasterDuke17/rakudo,nbrown/rakudo,nbrown/rakudo,nbrown/rakudo,salortiz/rakudo,rakudo/rakudo,Gnouc/rakudo,tbrowder/rakudo,salortiz/rakudo,rakudo/rakudo,nbrown/rakudo,softmoth/rakudo,MasterDuke17/rakudo,rakudo/rakudo,softmoth/rakudo,salortiz/rakudo,Gnouc/rakudo,rakudo/rakudo,labster/rakudo,salortiz/rakudo,MasterDuke17/rakudo,tbrowder/rakudo,softmoth/rakudo,labster/rakudo,salortiz/rakudo,tbrowder/rakudo,Gnouc/rakudo,tony-o/rakudo,softmoth/rakudo