Tag invoke parse result.

muppet/puppet/format/parser.py

@@ -434,7 +434,7 @@ class ParserFormatter(Serializer[ParseDirective]):
                 for x in xs:
                     parser &= ws & ',' & ws & self.s(x)
         parser &= optional(ws & ',') & optional(ws & ')')
-        return parser
+        return tag('invoke', parser)
 
     @override
     def _puppet_keyword(self, it: PuppetKeyword) -> ParseDirective: