Take on main_prometheus comments

prometheus-ksonnet/lib/prometheus.libsonnet

@@ -1,6 +1,16 @@
 {
-  prometheus: {
-    name:: 'prometheus',
+  /*
+   * All Prometheus resources are contained within a `prometheus` node. This allows
+     multiple Prometheus instances to be created by simply cloning this node, like
+     so:
+     `other_prometheus: $.prometheus {name: "other-prometheus"},`
+
+     To remove the default Prometheus, use this code:
+     `main_prometheus: {},`
+  */
+
+  prometheus:: {
+    name:: error 'must specify name',
 
     _config:: $._config,
 
@@ -111,4 +121,6 @@
     prometheus_service:
       $.util.serviceFor(self.prometheus_statefulset),
   },
+
+  main_prometheus: $.prometheus {name: "prometheus"},
 }