Clarify stale file removal text
Clarify stale file removal text

Make clear it's the process of installation (i. e. `make install`) and not the installed raku that will try to remove the files. Also get rid of a typo.
salortiz/rakudo,rakudo/rakudo,nbrown/rakudo,rakudo/rakudo,labster/rakudo,tbrowder/rakudo,tbrowder/rakudo,rakudo/rakudo,nbrown/rakudo,salortiz/rakudo,labster/rakudo,tony-o/rakudo,tony-o/rakudo,salortiz/rakudo,tbrowder/rakudo,rakudo/rakudo,softmoth/rakudo,softmoth/rakudo,MasterDuke17/rakudo,salortiz/rakudo,tbrowder/rakudo,softmoth/rakudo,MasterDuke17/rakudo,labster/rakudo,tbrowder/rakudo,softmoth/rakudo,tony-o/rakudo,labster/rakudo,nbrown/rakudo,rakudo/rakudo,nbrown/rakudo,tony-o/rakudo,salortiz/rakudo,softmoth/rakudo,nbrown/rakudo,labster/rakudo,MasterDuke17/rakudo,tony-o/rakudo,tbrowder/rakudo,MasterDuke17/rakudo,MasterDuke17/rakudo,MasterDuke17/rakudo,tony-o/rakudo,labster/rakudo,rakudo/rakudo,nbrown/rakudo,salortiz/rakudo