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://golang.org/cl/11034043

scryner/tour,LaPingvino/go-tour-eo,LaPingvino/go-tour-nl,scryner/tour,campoy/go-tour-ua,zorion/go-tour-ca,tamnd/tour,Go-zh/tour,bbandaru/tour,rofrol/go-tour-pl,phoorichet/tour,dupoxy/go-tour-fr,scryner/tour,rofrol/go-tour-pl,scryner/tour,shuLhan/tour,Go-zh/tour,tamnd/tour,phoorichet/tour,dupoxy/go-tour-fr,rofrol/go-tour-pl,LaPingvino/go-tour-eo,Jasperste/tour,LaPingvino/go-tour-nl,shuLhan/go-tour-id,shuLhan/tour,raindev/tour,campoy/go-tour-ua,tamnd/tour,dupoxy/go-tour-fr,raindev/tour,golians/tour,ybin/tour,ybin/tour,LaPingvino/go-tour-eo,golians/tour,shuLhan/go-tour-id,shuLhan/tour,golians/tour,Go-zh/tour,campoy/go-tour-ua,shuLhan/go-tour-id,LaPingvino/go-tour-nl,raindev/tour,bbandaru/tour,Go-zh/tour,Jasperste/tour,Jasperste/tour,zorion/go-tour-ca,phoorichet/tour,ybin/tour,bbandaru/tour,golang/tour