Add release labels to docs

Followup #238

Signed-off-by: Stefan Prodan <stefan.prodan@gmail.com>

Author: stefanprodan

docs/spec/v2beta1/helmreleases.md

@@ -747,6 +747,14 @@ The timeout for any individual Kubernetes operation (like Jobs for hooks) during
 of Helm actions can be configured via `spec.timeout` and can be overridden per action
 via `spec.<action>.timeout`.
 
+List all Kubernetes objects reconciled from a HelmRelease:
+
+```sh
+kubectl get all --all-namespaces \
+-l=helm.toolkit.fluxcd.io/name="<HelmRelease name>" \
+-l=helm.toolkit.fluxcd.io/namespace="<HelmRelease namespace>"
+```
+
 ### Disabling resource waiting
 
 For install, upgrade, and rollback actions resource waiting is enabled by default,