[x/tour] go-tour: link to screencast from final page of tour
[x/tour] go-tour: link to screencast from final page of tour

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/6852043
X-Tour-Commit: d6ce57d1cbfd801cc584a4f8cbb8761ba5a9adf3

golang/website,golang/website,golang/website,golang/website,golang/website,golang/website,golang/website