tour: change color on links to make them visible
tour: change color on links to make them visible

Fixes golang/go#13121

Change-Id: Id8bad9392fd78c6c816b4e6454269055881442f1
Reviewed-on: https://go-review.googlesource.com/17405
Reviewed-by: Minux Ma <72d850dbd8858b791995463d8539b5a379577f28@golang.org>

scryner/tour,golians/tour,scryner/tour,dupoxy/go-tour-fr,shuLhan/tour,shuLhan/go-tour-id,shuLhan/go-tour-id,shuLhan/tour,Go-zh/tour,Go-zh/tour,zorion/go-tour-ca,zorion/go-tour-ca,shuLhan/tour,Go-zh/tour,shuLhan/go-tour-id,Go-zh/tour,golians/tour,golians/tour,golang/tour,scryner/tour,dupoxy/go-tour-fr,dupoxy/go-tour-fr,scryner/tour