I found files to change with this command:

    git grep 'DO NOT EDIT' | grep -v 'Code generated .* DO NOT'

There are more files that match that grep, but I do not intend on fixing
them.

Change-Id: I4b474f1c29ca3135560d414785b0dbe0d1a4e52c
GitHub-Last-Rev: 65804b02634abd85bf113788b38354d48801241f
GitHub-Pull-Request: golang/go#24334
Reviewed-on: https://go-review.googlesource.com/99955Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>