content: reinstate instructions for running locally
content: reinstate instructions for running locally

This was lost in the conversion from HTML to present format in
6cf2ff.

Fixes golang/go#12134

Change-Id: I58a16ceb4a5edfbccb9733c3df2d409022bb6ffa
Reviewed-on: https://go-review.googlesource.com/15652
Reviewed-by: Andrew Gerrand <395a7d33bec8475c9b83b7d440f141bcbd994aa5@golang.org>

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