review: check form of commit messages

Fixes golang/go#9254

Change-Id: Iac4cc8474096209cd1b0f8ee812c0637babc2560
Reviewed-on: https://go-review.googlesource.com/1351
Reviewed-by: Russ Cox <rsc@golang.org>
2 files changed
tree: a0017d2c8e6c3c531ec0e95772e8d62e5827b43f
  1. README
  2. git-review/