Updated README to use '--formation monitor'. (#880)

Fixes #874

Author: chewygranola

README.md

@@ -154,7 +154,7 @@ Once the building and installation is done, follow those steps:
   2. Get the Postgres URI (connection string) for the monitor node:
 
      ~~~ bash
-     $ pg_autoctl show uri --monitor --pgdata ./monitor
+     $ pg_autoctl show uri --formation monitor 
 	 postgres://autoctl_node@localhost:5000/pg_auto_failover?sslmode=require
      ~~~
 

src/bin/pg_autoctl/cli_show.c

@@ -67,9 +67,8 @@ static void print_all_uri(SSLOptions *ssl,
 CommandLine show_uri_command =
 	make_command("uri",
 				 "Show the postgres uri to use to connect to pg_auto_failover nodes",
-				 " [ --pgdata --monitor --formation --json ] ",
+				 " [ --pgdata --formation --json ] ",
 				 "  --pgdata      path to data directory\n"
-				 "  --monitor     show the monitor uri\n"
 				 "  --formation   show the coordinator uri of given formation\n"
 				 "  --json        output data in the JSON format\n",
 				 cli_show_uri_getopts,
@@ -94,7 +93,7 @@ CommandLine show_state_command =
 				 "Prints monitor's state of nodes in a given formation and group",
 				 " [ --pgdata --formation --group ] ",
 				 "  --pgdata      path to data directory	 \n"
-				 "  --monitor     show the monitor uri\n"
+				 "  --monitor     pg_auto_failover Monitor Postgres URL\n"
 				 "  --formation   formation to query, defaults to 'default' \n"
 				 "  --group       group to query formation, defaults to all \n"
 				 "  --local       show local data, do not connect to the monitor\n"