doc: update codelab wiki to fix template.Execute argument order

Fixes #1595.

R=r
CC=golang-dev
https://golang.org/cl/4243067
diff --git a/doc/codelab/wiki/final-noerror.go b/doc/codelab/wiki/final-noerror.go
index 0f18912..5fcf1de 100644
--- a/doc/codelab/wiki/final-noerror.go
+++ b/doc/codelab/wiki/final-noerror.go
@@ -35,14 +35,14 @@
 		p = &Page{Title: title}
 	}
 	t, _ := template.ParseFile("edit.html", nil)
-	t.Execute(p, w)
+	t.Execute(w, p)
 }
 
 func viewHandler(w http.ResponseWriter, r *http.Request) {
 	title := r.URL.Path[lenPath:]
 	p, _ := loadPage(title)
 	t, _ := template.ParseFile("view.html", nil)
-	t.Execute(p, w)
+	t.Execute(w, p)
 }
 
 func main() {