chore(docs): add refference to metric ports

docs/docs/features/monitoring.md

@@ -66,7 +66,9 @@ The provided file is just a starting point. There are a ton of ways to configure
 After bringing down the containers with `docker compose down` and back up with `docker compose up -d`, a Prometheus instance will now collect metrics from the immich server and microservices containers. Note that we didn't need to expose any new ports for these containers - the communication is handled in the internal Docker network.
 
 :::note
-To see exactly what metrics are made available, you can additionally add `8081:8081` to the server container's ports and `8082:8082` to the microservices container's ports. Visiting the `/metrics` endpoint for these services will show the same raw data that Prometheus collects.
+To see exactly what metrics are made available, you can additionally add `8081:8081` to the server container's ports and `8082:8082` to the microservices container's ports.
+Visiting the `/metrics` endpoint for these services will show the same raw data that Prometheus collects.
+To configure these ports see [`IMMICH_API_METRICS_PORT` & `IMMICH_MICROSERVICES_METRICS_PORT`](../install/environment-variables/#general).
 :::
 
 ### Usage