Unify README and program help output PiperOrigin-RevId: 707525670 Change-Id: I35f1c58ed35661e71163d5693cf588a65c920a7e Reviewed-on: https://go-review.googlesource.com/c/open2opaque/+/637357 LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Michael Stapelberg <stapelberg@google.com> Reviewed-by: Chressie Himpel <chressie@google.com> Auto-Submit: Michael Stapelberg <stapelberg@google.com>