Release notes should always be files under doc/next. Make it clear that
this is the only way to add them: RELNOTE markers in CLs are no longer
supported.
Change-Id: I34d77eb876f57b84ecdc7e5ecbf3eb5c91e6fed8
Reviewed-on: https://go-review.googlesource.com/c/go/+/582075 Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
TryBot-Bypass: Jonathan Amsterdam <jba@google.com> Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>