It is not documented that pg_promote can exit standby mode

[ikedamsh]

Hi, 

The document(high-availability.sgml) says that there are only two ways 
to exit standby mode.

　26.2.2. Standby Server Operation
　Standby mode is exited and the server switches to normal operation when 
pg_ctl promote is run or a trigger file is found (promote_trigger_file).

But there is another way, by calling pg_promote function.
I think we need to document it, doesn't it?

I attached a patch. Please review and let me know your thoughts.

Regards,
Masahiro IkedaFrom 719b754c36f4537aaab7c6de1951d7b7ec4759f6 Mon Sep 17 00:00:00 2001
From: Masahiro Ikeda <ikeda...@oss.nttdata.com>
Date: Tue, 7 Apr 2020 08:34:55 +0900
Subject: [PATCH] fix doc about the way to exit standby mode

---
 doc/src/sgml/high-availability.sgml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml
index 4659b9e..88bf960 100644
--- a/doc/src/sgml/high-availability.sgml
+++ b/doc/src/sgml/high-availability.sgml
@@ -644,8 +644,8 @@ protocol to make nodes agree on a serializable transactional order.
 
    <para>
     Standby mode is exited and the server switches to normal operation
-    when <command>pg_ctl promote</command> is run or a trigger file is found
-    (<varname>promote_trigger_file</varname>). Before failover,
+    when <command>pg_ctl promote</command> is run, <function>pg_promote</function> is called,
+    or a trigger file is found(<varname>promote_trigger_file</varname>). Before failover,
     any WAL immediately available in the archive or in <filename>pg_wal</filename> will be
     restored, but no attempt is made to connect to the master.
    </para>
-- 
1.8.3.1