Please answer these questions before submitting your issue. Thanks!

1. What version of Go are you using (go version)? -
   go version go1.6 darwin/amd64
2. What operating system and processor architecture are you using (go env)?

GOARCH="amd64"
GOBIN=""
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOOS="darwin"
GOPATH="/Users/.../Source/go"
GORACE=""
GOROOT="/usr/local/Cellar/go/1.6/libexec"
GOTOOLDIR="/usr/local/Cellar/go/1.6/libexec/pkg/tool/darwin_amd64"
GO15VENDOREXPERIMENT="1"
CC="clang"
GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fno-common"
CXX="clang++"
CGO_ENABLED="1"

1. What did you do?
   go codereview mail -h describes an option, -trybot, but neither go codereview help nor https://godoc.org/golang.org/x/review/git-codereview describes the option
2. What did you expect to see?
   Something telling me what the -trybot option does (esp. if I can use it).
3. What did you see instead?
   Nothing telling me what -trybot does.