websocket: don't recommend Gorilla

It's no longer maintained.

Fixes golang/go#57228

Change-Id: I6678d1959a36761477e5c634c21305f775c80761
Reviewed-on: https://go-review.googlesource.com/c/net/+/457356
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Ian Lance Taylor <iant@golang.org>

websocket/websocket.go

@@ -5,11 +5,10 @@
 // Package websocket implements a client and server for the WebSocket protocol
 // as specified in RFC 6455.
 //
-// This package currently lacks some features found in alternative
-// and more actively maintained WebSocket packages:
+// This package currently lacks some features found in an alternative
+// and more actively maintained WebSocket package:
 //
-//	https://godoc.org/github.com/gorilla/websocket
-//	https://godoc.org/nhooyr.io/websocket
+//	https://pkg.go.dev/nhooyr.io/websocket
 package websocket // import "golang.org/x/net/websocket"
 
 import (