godoc: use FormatText for formating code in html template.
godoc: use FormatText for formating code in html template.

R=golang-dev, rsc, r, adg, gri, r
CC=golang-dev
http://codereview.appspot.com/5835046

Committer: Robert Griesemer <a6752097faebf1f02d80107d77a9be009089afe3@golang.org>

h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang