content: fix a link and update text of "Six years" article

Change-Id: I02182cd5d13dcd3d588588f892f297d85635c219
Reviewed-on: https://go-review.googlesource.com/16755
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Andrew Gerrand <adg@golang.org>
1 file changed