Streamline World.install_lexical_magical a bit
Streamline World.install_lexical_magical a bit

- document it also being used for $¢
- common case has one existskey less
- don't lookup $*W, it's the same as self

Should help a *little* bit in compilation

tbrowder/rakudo,tbrowder/rakudo,labster/rakudo,tbrowder/rakudo,labster/rakudo,salortiz/rakudo,tbrowder/rakudo,MasterDuke17/rakudo,labster/rakudo,rakudo/rakudo,salortiz/rakudo,rakudo/rakudo,salortiz/rakudo,MasterDuke17/rakudo,rakudo/rakudo,rakudo/rakudo,MasterDuke17/rakudo,tbrowder/rakudo,labster/rakudo,salortiz/rakudo,MasterDuke17/rakudo,labster/rakudo,labster/rakudo,tbrowder/rakudo,salortiz/rakudo,rakudo/rakudo,MasterDuke17/rakudo,salortiz/rakudo,MasterDuke17/rakudo,rakudo/rakudo