fix grammar error: the predicate verb should be the third person.

cmd/kubeadm/app/cmd/cmd.go

@@ -28,7 +28,7 @@ import (
 	// depends on the generated defaults.
 )
 
-// NewKubeadmCommand return cobra.Command to run kubeadm command
+// NewKubeadmCommand returns cobra.Command to run kubeadm command
 func NewKubeadmCommand(in io.Reader, out, err io.Writer) *cobra.Command {
 	cmds := &cobra.Command{
 		Use:   "kubeadm",

cmd/kubeadm/app/cmd/phases/controlplane.go

@@ -63,7 +63,7 @@ var (
 		`+cmdutil.AlphaDisclaimer), kubeadmconstants.GetStaticPodFilepath(kubeadmconstants.KubeScheduler, kubeadmconstants.GetStaticPodDirectory()))
 )
 
-// NewCmdControlplane return main command for Controlplane phase
+// NewCmdControlplane returns main command for Controlplane phase
 func NewCmdControlplane() *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "controlplane",

cmd/kubeadm/app/cmd/phases/etcd.go

@@ -45,7 +45,7 @@ var (
 		`)
 )
 
-// NewCmdEtcd return main command for Etcd phase
+// NewCmdEtcd returns main command for Etcd phase
 func NewCmdEtcd() *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "etcd",

cmd/kubeadm/app/cmd/phases/kubeconfig.go

@@ -75,7 +75,7 @@ var (
 		`)
 )
 
-// NewCmdKubeConfig return main command for kubeconfig phase
+// NewCmdKubeConfig returns main command for kubeconfig phase
 func NewCmdKubeConfig(out io.Writer) *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "kubeconfig",