go.tools/godoc: restore line anchors to the source view.
go.tools/godoc: restore line anchors to the source view.

These were removed when adding the -analysis flag (CL
60540044), ostensibly for performance, but I can't reproduce
the serious slowdowns I saw then.  In any case, they are
needed for certain URLs.

Fixes golang/go#7743

LGTM=bgarcia
R=bgarcia
CC=golang-codereviews
https://golang.org/cl/86150043

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