_content/tour: delete link to offline zh translation

The link to the Simplified Chinese translation of the Tour has been
dead for a while, delete it.

Change-Id: Iff15f1656a69a9d4cc36fb392ea7a8a733976ff5
Reviewed-on: https://go-review.googlesource.com/c/website/+/816880
LUCI-TryBot-Result: golang-scoped@luci-project-accounts.iam.gserviceaccount.com <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Sean Liao <sean@liao.dev>
diff --git a/_content/tour/welcome.article b/_content/tour/welcome.article
index e373b38..2c2c3d0 100644
--- a/_content/tour/welcome.article
+++ b/_content/tour/welcome.article
@@ -49,7 +49,6 @@
 
 - [[https://go-tour-br.appspot.com/][Brazilian Portuguese — Português do Brasil]]
 - [[https://go-tour-ca.appspot.com/][Catalan — Català]]
-- [[https://tour.go-zh.org/][Simplified Chinese — 中文(简体)]]
 - [[https://go-tour-cz.appspot.com/][Czech — Česky]]
 - [[https://go-tour-id2.appspot.com/][Indonesian — Bahasa Indonesia]]
 - [[https://go-tour-jp.appspot.com/][Japanese — 日本語]]