fix: ignore short flags too when finding pulled image

Signed-off-by: Yves Brissaud <yves.brissaud@docker.com>

Author: eunomie

cli/mobycli/scout_suggest.go

@@ -64,7 +64,7 @@ func pulledImageFromArgs(args []string) string {
 			pull = true
 			continue
 		}
-		if pull && !strings.HasPrefix(a, "--") {
+		if pull && !strings.HasPrefix(a, "-") {
 			image = a
 			break
 		}