[S06] avoid indirect method call syntax

It is unrelated to the topic, and seem to confuse readers. Me too.

S06-routines.pod

@@ -540,7 +540,7 @@ or a specially tied proxy object, with suitably programmed
 C<FETCH> and C<STORE> methods:
 
     sub checklastval ($passwd) is rw {
-        return new Proxy:
+        return Proxy.new:
                 FETCH => method {
                             return lastval();
                          },