[release-branch.go1.16] cmd/go: remove hint when no module is suggested

Updates #46528
Fixes #46551

Change-Id: I2453d321ece878ea7823865758aa4a16b3ed7fe8
Reviewed-on: https://go-review.googlesource.com/c/go/+/325430


Reviewed-by: Bryan C. Mills <bcmills@google.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Trust: Heschi Kreinick <heschi@google.com>
Trust: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
(cherry picked from commit e552a6d3)
Reviewed-on: https://go-review.googlesource.com/c/go/+/334371


Trust: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Jay Conrod <jayconrod@google.com>
Reviewed-by: Michael Matloob <matloob@golang.org>