doc/effective_go.html: replace tab with spaces.
doc/effective_go.html: replace tab with spaces.

R=golang-dev, gri
CC=golang-dev
http://codereview.appspot.com/4609042
abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go