Add a quick package doc for the servers package

consul/servers/manager.go

@@ -1,3 +1,8 @@
+// Package servers provides a Manager interface for Manager managed
+// server_details.ServerDetails objects.  The servers package manages servers
+// from a Consul client's perspective (i.e. a list of servers that a client
+// talks with for RPCs).  The servers package does not provide any API
+// guarantees and should be called only by `hashicorp/consul`.
 package servers
 
 import (