kubectl: rewrite docstrings in several files

Fixing inaccuracies and clarifying in the case of ambiguities.

pkg/kubectl/cmd/create_deployment.go

@@ -38,7 +38,9 @@ var (
     kubectl create deployment my-dep --image=busybox`))
 )
 
-// NewCmdCreateDeployment is a macro command to create a new deployment
+// NewCmdCreateDeployment is a macro command to create a new deployment.
+// This command is better known to users as `kubectl create deployment`.
+// Note that this command overlaps significantly with the `kubectl run` command.
 func NewCmdCreateDeployment(f cmdutil.Factory, cmdOut, cmdErr io.Writer) *cobra.Command {
 	cmd := &cobra.Command{
 		Use:     "deployment NAME --image=image [--dry-run]",