go-tour: add missing error/rune predeclared identifier for Syntax-Highlighting
go-tour: add missing error/rune predeclared identifier for Syntax-Highlighting

R=golang-dev, khr, adg
CC=golang-dev
https://codereview.appspot.com/11034043

Committer: Andrew Gerrand <395a7d33bec8475c9b83b7d440f141bcbd994aa5@golang.org>

minux/go-tour-zh,Go-zh/tour-old,Go-zh/tour-old,minux/go-tour-zh