Add a comment about the readyz probe

cmd/kueue/main.go

@@ -279,6 +279,14 @@ func setupProbeEndpoints(mgr ctrl.Manager) {
 		setupLog.Error(err, "unable to set up health check")
 		os.Exit(1)
 	}
+
+	// Wait for the webhook server to be listening before exposing the
+	// Kueue replica as ready. This allows users to wait with first requests
+	// until the Kueue deployment is available, so that the early requests are
+	// not rejected during startup.
+	// We wrap the call to GetWebhookServer in a closure to delay calling
+	// the function, otherwise a not fully-initialized webook server is used for
+	// the checks.
 	if err := mgr.AddReadyzCheck("readyz", func(req *http.Request) error {
 		return mgr.GetWebhookServer().StartedChecker()(req)
 	}); err != nil {