Since the slice of names is almost exactly the same as what stringer is
already generating for us.

Passes toolstash -cmp on std cmd.

Change-Id: I3f1e95efc690c0108236689e721627f00f79a461
Reviewed-on: https://go-review.googlesource.com/77190
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>