tiup: add instructions for the --local option (#16097)

tiup/tiup-component-cluster-template.md

@@ -28,6 +28,11 @@ If this option is not specified, the output default template contains the follow
 - Outputs a detailed topology template that is commented with configurable parameters. To enable this option, add it to the command.
 - If this option is not specified, the simple topology template is output by default.
 
+### --local
+
+- Outputs a simple topology template for the local cluster, which can be used directly, and the `global` parameter can be adjusted as needed.
+- This template creates a PD service, a TiDB service, a TiKV service, a monitoring service, and a Grafana service.
+
 ### --multi-dc
 
 - Outputs the topology template of multiple data centers. To enable this option, add it to the command.