Remove some unneeded (double) stubs

src/core/Any.pm

@@ -1,10 +1,6 @@
-my class Bag { ... }
-my class KeyBag { ... }
-my class KeySet { ... }
 my class MapIter { ... }
 my class Pair { ... }
 my class Range { ... }
-my class Set { ... }
 my class X::Bind::Slice { ... }
 my class X::Bind::ZenSlice { ... }
 

src/core/stubs.pm

@@ -7,6 +7,7 @@ my class Whatever { ... }
 my class Bag { ... }
 my class KeyBag { ... }
 my class KeySet { ... }
+my class Set { ... }
 my class KeyHash is Iterable does Associative { }
 my class Seq is List does Positional { }
 my class Exception { ... }