style: fmt code

jsonnet/kube-prometheus/components/prometheus.libsonnet

@@ -128,7 +128,7 @@ function(params) {
           port: 9090,
           protocol: 'TCP',
         }],
-      }] + ( if p._config.thanos != null then
+      }] + (if p._config.thanos != null then
               [{
                 from: [{
                   podSelector: {