go.tools/cmd/godoc: add redirect helpers
go.tools/cmd/godoc: add redirect helpers

Previously these helpers were added by a private deployment script.
There's no reason why they shouldn't be part of godoc proper now
that it's in the go.tools repository.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/13722043

nicot/tools,glasser/golang-tools,cmars/tools,josharian/tools,argandas/tools,dmitris/tools,magiccao/tools,jdhenke/tools,cw2018/tools,cw2018/tools,matryer/tools,maddyonline/tools,magiccao/tools,sshetty10/tools,golang/tools,argandas/tools,syreclabs/go-tools,springning/tools,sshetty10/tools,dmitris/tools,golang/tools,cw2018/tools,runcom/tools,dmitris/tools,maddyonline/tools,glasser/golang-tools,springning/tools,josharian/tools,cmars/tools,maddyonline/tools,sshetty10/tools,magiccao/tools,nicot/tools,syreclabs/go-tools,argandas/tools,golang/tools,matryer/tools,4ad/tools,cw2018/tools,syreclabs/go-tools,syreclabs/go-tools,4ad/tools,magiccao/tools,sshetty10/tools,springning/tools,runcom/tools,nicot/tools,nicot/tools,josharian/tools,golang/tools,dmitris/tools,glasser/golang-tools,golang/tools,maddyonline/tools,matryer/tools,syreclabs/go-tools,syreclabs/go-tools,4ad/tools,cmars/tools,runcom/tools,runcom/tools,jdhenke/tools,springning/tools,josharian/tools,cmars/tools,glasser/golang-tools,jdhenke/tools,argandas/tools,matryer/tools,jdhenke/tools