cmd/docker: render hints from errors that carry them

Hooks the new internal/hint package into the top-level error renderer.
After printing the error itself, walks the chain for any error
implementing hint.Hinter and prints its hint on its own line. This
makes hints a first-class output, separate from the error message,
without changing how errors are constructed or wrapped at call sites
that don't carry a hint.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Signed-off-by: David Karlsson <35727626+dvdksn@users.noreply.github.com>

Author: dvdksn

cmd/docker/docker.go

@@ -24,6 +24,7 @@ import (
 	cliflags "github.com/docker/cli/cli/flags"
 	"github.com/docker/cli/cli/version"
 	platformsignals "github.com/docker/cli/cmd/docker/internal/signals"
+	"github.com/docker/cli/internal/hint"
 	"github.com/moby/moby/client/pkg/versions"
 	"github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
@@ -48,6 +49,9 @@ func main() {
 	if err != nil && !errdefs.IsCanceled(err) {
 		if err.Error() != "" {
 			_, _ = fmt.Fprintln(os.Stderr, err)
+			if h := hint.Of(err); h != "" {
+				_, _ = fmt.Fprintln(os.Stderr, "\n"+h)
+			}
 		}
 		os.Exit(getExitCode(err))
 	}