internal/tour: fix go.dev/tour

The playground js was coming from
godoc instead of the updated copy in go.dev.

Change-Id: I26be8634b0e5d453b966be758f08c15b4bc7ca72
Reviewed-on: https://go-review.googlesource.com/c/website/+/366376
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Website-Publish: Russ Cox <rsc@golang.org>
diff --git a/content.go b/content.go
index 40ea366..4b8b447 100644
--- a/content.go
+++ b/content.go
@@ -23,7 +23,10 @@
 //go:embed _content
 var embedded embed.FS
 
-//go:embed _content/tour _content/favicon.ico _content/images/go-logo-white.svg
+//go:embed _content/favicon.ico
+//go:embed _content/images/go-logo-white.svg
+//go:embed _content/js/playground.js
+//go:embed _content/tour
 var tourOnly embed.FS
 
 func subdir(fsys fs.FS, path string) fs.FS {