Clarify items in the sample repmgr.conf file

Based on customer feedback.

repmgr.conf.sample

@@ -18,9 +18,13 @@ cluster=example_cluster
 #  replication funcion, as this will cause confusion when e.g.
 #  "standby2" is promoted to primary)
 node=2           # a unique integer
-node_name=node2  # an arbitrary (but unique) string
+node_name=node2  # an arbitrary (but unique) string; we recommend using
+                 # the server's hostname or another identifier unambiguously
+                 # associated with the server to avoid confusion
 
-# Database connection information
+# Database connection information as a conninfo string
+# This must be accessible to all servers in the cluster; for details see:
+#   http://www.postgresql.org/docs/current/static/libpq-connect.html#LIBPQ-CONNSTRING
 conninfo='host=192.168.204.104 dbname=repmgr_db user=repmgr_usr'
 
 # Optional configuration items