talks: add to 2016/refactor.article a link to issue 18130 Change-Id: I14b9ada64e25c6ba0530fabbd24e8ff98c252979 Reviewed-on: https://go-review.googlesource.com/33724 Run-TryBot: Russ Cox <rsc@golang.org> Reviewed-by: Russ Cox <rsc@golang.org>