message: add some more examples

to at least show it can take and substitute
translated format strings

Change-Id: Ibd8384655986b266c0f1355537d61c06d0663474
Reviewed-on: https://go-review.googlesource.com/60772
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Nigel Tao <nigeltao@golang.org>
diff --git a/message/doc.go b/message/doc.go
index 60424a6..89c1592 100644
--- a/message/doc.go
+++ b/message/doc.go
@@ -14,6 +14,11 @@
 //    p := message.NewPrinter(language.English)
 //    p.Println(123456.78) // Prints 123,456.78
 //
+//    p.Printf("%d ducks in a row", 4331) // Prints 4,331 ducks in a row
+//
+//    p := message.NewPrinter(language.Dutch)
+//    p.Println("Hoogte: %f meter", 1244.9) // Prints Hoogte: 1.244,9 meter
+//
 //    p := message.NewPrinter(language.Bengali)
 //    p.Println(123456.78) // Prints ১,২৩,৪৫৬.৭৮
 //