docs: [#246] Add note about upcoming show command for getting VM IP

Added helpful tip in grafana-verification.md mentioning the planned
'show' command (issue #241) that will provide a more user-friendly
way to display environment information including the IP address.

Current jq command remains as the working method until the feature
is implemented.

Author: josecelano

docs/e2e-testing/manual/grafana-verification.md

@@ -50,6 +50,12 @@ Extract the instance IP from the environment state (see [main guide](README.md#s
 cat data/<env-name>/environment.json | jq -r '.Running.context.runtime_outputs.instance_ip'
 ```
 
+> **💡 Tip**: A `show` command is planned (issue [#241](https://github.com/torrust/torrust-tracker-deployer/issues/241)) that will display environment information including the IP address in a more user-friendly format. Once implemented, you'll be able to use:
+>
+> ```bash
+> cargo run -- show <env-name>
+> ```
+
 ## Verification Steps
 
 ### 1. Verify Grafana Container is Running