gc: fix comments in go.h
gc: fix comments in go.h

Trivial fix to '// n' comments against etype enum in go.h, as these have
got out of sync.

R=golang-dev, gri
CC=golang-dev
http://codereview.appspot.com/4240097

Committer: Robert Griesemer <a6752097faebf1f02d80107d77a9be009089afe3@golang.org>

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