Minor comments fix

Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>

main.go

@@ -23,12 +23,12 @@ direct child of the process supervisor.
 After creating a spec for your root filesystem with runc, you can execute a
 container in your shell by running:
 
-    cd /mycontainer
-    runc start
+    # cd /mycontainer
+    # runc start
 
 or
-	cd /mycontainer
-	runc start [ spec-file ]
+    # cd /mycontainer
+    # runc start [ spec-file ]
 
 If not specified, the default value for the 'spec-file' is 'config.json'. `
 )
@@ -87,7 +87,7 @@ func main() {
 		}
 		return nil
 	}
-	// Default to 'start' is no command is specified
+	// Default to 'start' if no command is specified
 	app.Action = startCommand.Action
 	if err := app.Run(os.Args); err != nil {
 		logrus.Fatal(err)