Docs: add reference to flog CLI args (#9638)

**What this PR does / why we need it**:

**Which issue(s) this PR fixes**:
Fixes #<issue number>

**Special notes for your reviewer**:

**Checklist**
- [x] Reviewed the
[`CONTRIBUTING.md`](https://github.com/grafana/loki/blob/main/CONTRIBUTING.md)
guide (**required**)
- [x] Documentation added
- [ ] Tests updated
- [ ] `CHANGELOG.md` updated
- [ ] Changes that require user attention or interaction to upgrade are
documented in `docs/sources/upgrading/_index.md`
- [ ] For Helm chart changes bump the Helm chart version in
`production/helm/loki/Chart.yaml` and update
`production/helm/loki/CHANGELOG.md` and
`production/helm/loki/README.md`. [Example
PR](d10549e3ec)

docs/sources/get-started/_index.md

@@ -124,7 +124,7 @@ Choose one of these two ways to apply a new configuration:
         ```
         docker-compose down
         ```
-    1. Edit the `docker-compose.yaml` file.  Within the YAML file, change the `flog.command` field's value to specify your flog output.
+    1. Edit the `docker-compose.yaml` file.  Within the YAML file, change the `flog.command` field's value to specify your flog output. Refer to the `flog` [command line arguments](https://hub.docker.com/r/mingrammer/flog).
     1. With `evaluate-loki` as the current working directory, instantiate the new test environment:
         ```
         docker-compose up -d