Amtool and Alertmanager binaries print to stdout

Signed-off-by: ArthurSens <arthursens2005@gmail.com>

cli/root.go

@@ -89,7 +89,7 @@ func NewAlertmanagerClient(amURL *url.URL) *client.Alertmanager {
 // Execute is the main function for the amtool command
 func Execute() {
 	var (
-		app = kingpin.New("amtool", helpRoot)
+		app = kingpin.New("amtool", helpRoot).UsageWriter(os.Stdout)
 	)
 
 	format.InitFormatFlags(app)

cmd/alertmanager/main.go

@@ -210,6 +210,7 @@ func run() int {
 	)
 
 	promlogflag.AddFlags(kingpin.CommandLine, &promlogConfig)
+	kingpin.CommandLine.UsageWriter(os.Stdout)
 
 	kingpin.Version(version.Print("alertmanager"))
 	kingpin.CommandLine.GetFlag("help").Short('h')