doc/1.17: fix two dead rfc links
doc/1.17: fix two dead rfc links

Updates #44513

Change-Id: Ia0c6b48bde2719f3a99cb216b6166d82159198d1
Reviewed-on: https://go-review.googlesource.com/c/go/+/336930
Trust: Alberto Donizetti <90b16103a35511ced020676f3544f17117fb4c92@gmail.com>
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>

golang/go,golang/go,nawawi/go,golang/go,cloudflare/go,nawawi/go,golang/go,nawawi/go,golang/go,cloudflare/go,CAFxX/go,CAFxX/go,nawawi/go,CAFxX/go,CAFxX/go,cloudflare/go,cloudflare/go,golang/go,nawawi/go,golang/go,CAFxX/go,nawawi/go,CAFxX/go,cloudflare/go,cloudflare/go,CAFxX/go,cloudflare/go,nawawi/go,nawawi/go,cloudflare/go,golang/go,CAFxX/go