Swift: mark BuiltinTuple as experimental

Author: AlexDenisov

swift/extractor/infra/SwiftTagTraits.h

@@ -217,7 +217,7 @@ MAP(swift::Decl, DeclTag)
           MAP(swift::StructDecl, StructDeclTag)
           MAP(swift::ClassDecl, ClassDeclTag)
           MAP(swift::ProtocolDecl, ProtocolDeclTag)
-          MAP(swift::BuiltinTupleDecl, void)  // TODO (introduced in 5.8)
+          MAP(swift::BuiltinTupleDecl, void)  // TODO, experimental
         MAP(swift::OpaqueTypeDecl, OpaqueTypeDeclTag)
         MAP(swift::TypeAliasDecl, TypeAliasDeclTag)
       MAP(swift::GenericTypeParamDecl, GenericTypeParamDeclTag)
@@ -302,7 +302,7 @@ MAP(swift::TypeBase, TypeTag)
         MAP(swift::StructType, StructTypeTag)
         MAP(swift::ClassType, ClassTypeTag)
         MAP(swift::ProtocolType, ProtocolTypeTag)
-        MAP(swift::BuiltinTupleType, void)  // TODO (introduced in 5.8)
+        MAP(swift::BuiltinTupleType, void)  // TODO, experimental
       MAP(swift::BoundGenericType, BoundGenericTypeTag)
         MAP(swift::BoundGenericClassType, BoundGenericClassTypeTag)
         MAP(swift::BoundGenericEnumType, BoundGenericEnumTypeTag)