tutorial: fix 404 link in web-service-gin

The link to the Gin docs was returning a 404 error
updated the link to point to en/docs from /docs.

Fixes golang/go#76040

Change-Id: Ibfb5d090aa3e3771538ee93252bd3c1529ef3965
GitHub-Last-Rev: 193c6fe295766ed095bc10bbba05d140c9752c49
GitHub-Pull-Request: golang/tour#1766
Reviewed-on: https://go-review.googlesource.com/c/tour/+/714540
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Bypass: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
diff --git a/tutorial/web-service-gin.md b/tutorial/web-service-gin.md
index b471cb7..a556047 100644
--- a/tutorial/web-service-gin.md
+++ b/tutorial/web-service-gin.md
@@ -9,7 +9,7 @@
 # Developing a RESTful API with Go and Gin
 
 This tutorial introduces the basics of writing a RESTful web service API with Go
-and the [Gin Web Framework](https://gin-gonic.com/docs/) (Gin).
+and the [Gin Web Framework](https://gin-gonic.com/en/docs/) (Gin).
 
 You'll get the most out of this tutorial if you have a basic familiarity with Go
 and its tooling. If this is your first exposure to Go, please see
@@ -574,7 +574,7 @@
 *   The [Go Tour](https://tour.golang.org/welcome/1) is a great step-by-step
     introduction to Go fundamentals.
 *   For more about Gin, see the [Gin Web Framework package documentation](https://pkg.go.dev/github.com/gin-gonic/gin)
-    or the [Gin Web Framework docs](https://gin-gonic.com/docs/).
+    or the [Gin Web Framework docs](https://gin-gonic.com/en/docs/).
 
 Continue to the next section to view the full code for the application you build
 with this tutorial.