unicode: modify a comment to the convention format.

R=golang-dev, r, rsc
CC=golang-dev
https://codereview.appspot.com/7869043

Committer: Russ Cox <rsc@golang.org>
cmd/gc: support channel types in the garbage collector

R=golang-dev, dvyukov, rsc
CC=golang-dev
https://codereview.appspot.com/7473044