internal/short: point to new tracking issue for shortlink creation

Applies CL 160377 from the x/tools repo to the x/website repo.

Updates golang/go#29206

Change-Id: I3c8b6a2ef5288cc84378c34a3a768952bf12df08
Reviewed-on: https://go-review.googlesource.com/c/162377
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/internal/short/short.go b/internal/short/short.go
index 69e82dc..c04e789 100644
--- a/internal/short/short.go
+++ b/internal/short/short.go
@@ -52,11 +52,11 @@
 	// TODO(cbro): move storage of the links to a text file in Gerrit.
 	// Disable the admin handler until that happens, since GAE Flex doesn't support
 	// the "google.golang.org/appengine/user" package.
-	// See golang.org/issue/27205#issuecomment-418673218
+	// See golang.org/issue/29988 and golang.org/issue/27205#issuecomment-418673218.
 	// mux.HandleFunc(prefix, adminHandler)
 	mux.HandleFunc(prefix, func(w http.ResponseWriter, r *http.Request) {
 		w.WriteHeader(http.StatusForbidden)
-		io.WriteString(w, "Link creation temporarily unavailable. See golang.org/issue/27205.")
+		io.WriteString(w, "Link creation temporarily unavailable. See golang.org/issue/29988.")
 	})
 }