Improve error for [ ] called with a type object
Improve error for [ ] called with a type object

Previous error was difficult to understand, and doesn't use the
same terminology we use for other error messages.

usev6/rakudo,rakudo/rakudo,Gnouc/rakudo,usev6/rakudo,sjn/rakudo,usev6/rakudo,nbrown/rakudo,sjn/rakudo,awwaiid/rakudo,salortiz/rakudo,tbrowder/rakudo,MasterDuke17/rakudo,rakudo/rakudo,sjn/rakudo,labster/rakudo,labster/rakudo,salortiz/rakudo,MasterDuke17/rakudo,tbrowder/rakudo,tbrowder/rakudo,sjn/rakudo,rakudo/rakudo,labster/rakudo,MasterDuke17/rakudo,usev6/rakudo,tony-o/rakudo,softmoth/rakudo,labster/rakudo,raydiak/rakudo,softmoth/rakudo,lucasbuchala/rakudo,tbrowder/rakudo,lucasbuchala/rakudo,salortiz/rakudo,nbrown/rakudo,tony-o/rakudo,jonathanstowe/rakudo,MasterDuke17/rakudo,labster/rakudo,nbrown/rakudo,awwaiid/rakudo,jonathanstowe/rakudo,jonathanstowe/rakudo,nbrown/rakudo,Gnouc/rakudo,softmoth/rakudo,tbrowder/rakudo,Gnouc/rakudo,rakudo/rakudo,lucasbuchala/rakudo,nbrown/rakudo,lucasbuchala/rakudo,salortiz/rakudo,rakudo/rakudo,raydiak/rakudo,labster/rakudo,tony-o/rakudo,salortiz/rakudo,jonathanstowe/rakudo,Gnouc/rakudo,tony-o/rakudo,Gnouc/rakudo,raydiak/rakudo,tbrowder/rakudo,nbrown/rakudo,MasterDuke17/rakudo,salortiz/rakudo,tony-o/rakudo,softmoth/rakudo,Gnouc/rakudo,MasterDuke17/rakudo,sjn/rakudo,raydiak/rakudo,rakudo/rakudo,tony-o/rakudo,softmoth/rakudo,awwaiid/rakudo,awwaiid/rakudo,awwaiid/rakudo,jonathanstowe/rakudo,lucasbuchala/rakudo,usev6/rakudo