template: remove reference to json-template
template: remove reference to json-template

Rather than confuse people by linking to a spec we
don't fully support, let them just use the package docs.

R=r, rsc
CC=golang-dev
http://codereview.appspot.com/1016041
abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go