http2: update docs to disrecommend this package

Every supported feature of the HTTP/2 client and server
is accessible via the net/http package. Recommend that
users use net/http rather than importing this package.

For #67810

Change-Id: I58b9c65af27e2f7172af493f96ee589a6a6a6964
Reviewed-on: https://go-review.googlesource.com/c/net/+/752160
Reviewed-by: Nicholas Husin <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: Nicholas Husin <[email protected]>
Auto-Submit: Damien Neil <[email protected]>

Author: neild

http2/http2.go

@@ -4,13 +4,17 @@
 
 // Package http2 implements the HTTP/2 protocol.
 //
-// This package is low-level and intended to be used directly by very
-// few people. Most users will use it indirectly through the automatic
-// use by the net/http package (from Go 1.6 and later).
-// For use in earlier Go versions see ConfigureServer. (Transport support
-// requires Go 1.6 or later)
+// Almost no users should need to import this package directly.
+// The net/http package supports HTTP/2 natively.
 //
-// See https://http2.github.io/ for more information on HTTP/2.
+// To enable or disable HTTP/2 support in net/http clients and servers, see
+// [http.Transport.Protocols] and [http.Server.Protocols].
+//
+// To configure HTTP/2 parameters, see
+// [http.Transport.HTTP2] and [http.Server.HTTP2].
+//
+// To create HTTP/1 or HTTP/2 connections, see
+// [http.Transport.NewClientConn].
 package http2 // import "golang.org/x/net/http2"
 
 import (