clarify s/annotation/label/ (#3351)

Author: rsalmond

annotation/annotations.gen.go

@@ -56,7 +56,8 @@ annotations:
   - name: sidecar.istio.io/inject
     featureStatus: Beta
     description: Specifies whether or not an Envoy sidecar should be automatically
-      injected into the workload. Deprecated in favor of `sidecar.istio.io/inject` label.
+      injected into the workload. This annotation has been deprecated in favor of the
+      `sidecar.istio.io/inject` label documented [here](/docs/reference/config/labels/#SidecarInject).
     deprecated: true
     hidden: false
     resources: