Documentation feedback on /docs/admin/troubleshooting/jcmd/docker.rst

### Documentation feedback

- Page title: Using jcmd with CrateDB on Docker
- Page URL: https://cratedb.com/docs/guide/admin/troubleshooting/jcmd/docker.html
- Source: https://github.com/crate/cratedb-guide/blob/main/docs/admin/troubleshooting/jcmd/docker.rst

---

The page talks exclusively about Docker, but could be generalized to containerized deployments to also cover `crate-operator` deployments.
Commands look slightly different for `kubectl`. Example:

```bash
# JFR Docker
docker exec -it --user=crate cratedb /crate/jdk/bin/jcmd 1 JFR.start name=recording1 duration=60s filename=/data/recording1.jfr

# JFR kubectl (--user parameter becomes su)
kubectl exec -it -n 6d1f152b-4ac1-459e-9a6c-96557c703872 crate-data-hot-f4ae0c70-1438-46cf-a577-abff62c3593a-0 -c crate -- su crate -c "/crate/jdk/bin/jcmd 1 JFR.start name=recording1 duration=60s filename=/data/recording1.jfr"
```