doc: document that INFO messages always go to client.

In passing add a couple of links to the message severity table.

Backpatch because it's always been this way.

Author: Karl O. Pinc <kop@meme.com>

Author: RhodiumToad

doc/src/sgml/config.sgml

@@ -4579,12 +4579,13 @@ local0.*    /var/log/postgresql
       </term>
       <listitem>
        <para>
-        Controls which message levels are written to the server log.
-        Valid values are <literal>DEBUG5</>, <literal>DEBUG4</>,
-        <literal>DEBUG3</>, <literal>DEBUG2</>, <literal>DEBUG1</>,
-        <literal>INFO</>, <literal>NOTICE</>, <literal>WARNING</>,
-        <literal>ERROR</>, <literal>LOG</>, <literal>FATAL</>, and
-        <literal>PANIC</>.  Each level includes all the levels that
+        Controls which <link linkend="runtime-config-severity-levels">message
+        levels</link> are written to the server log.
+        Valid values are <literal>DEBUG5</literal>, <literal>DEBUG4</literal>,
+        <literal>DEBUG3</literal>, <literal>DEBUG2</literal>, <literal>DEBUG1</literal>,
+        <literal>INFO</literal>, <literal>NOTICE</literal>, <literal>WARNING</literal>,
+        <literal>ERROR</literal>, <literal>LOG</literal>, <literal>FATAL</literal>, and
+        <literal>PANIC</literal>.  Each level includes all the levels that
         follow it.  The later the level, the fewer messages are sent
         to the log.  The default is <literal>WARNING</>.  Note that
         <literal>LOG</> has a different rank here than in
@@ -4605,7 +4606,9 @@ local0.*    /var/log/postgresql
         Controls which SQL statements that cause an error
         condition are recorded in the server log.  The current
         SQL statement is included in the log entry for any message of
-        the specified severity or higher.
+        the specified
+        <link linkend="runtime-config-severity-levels">severity</link>
+        or higher.
         Valid values are <literal>DEBUG5</literal>,
         <literal>DEBUG4</literal>, <literal>DEBUG3</literal>,
         <literal>DEBUG2</literal>, <literal>DEBUG1</literal>,
@@ -5905,16 +5908,21 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv;
       </term>
       <listitem>
        <para>
-        Controls which message levels are sent to the client.
-        Valid values are <literal>DEBUG5</>,
-        <literal>DEBUG4</>, <literal>DEBUG3</>, <literal>DEBUG2</>,
-        <literal>DEBUG1</>, <literal>LOG</>, <literal>NOTICE</>,
-        <literal>WARNING</>, and <literal>ERROR</>.
+        Controls which
+        <link linkend="runtime-config-severity-levels">message levels</link>
+        are sent to the client.
+        Valid values are <literal>DEBUG5</literal>,
+        <literal>DEBUG4</literal>, <literal>DEBUG3</literal>, <literal>DEBUG2</literal>,
+        <literal>DEBUG1</literal>, <literal>LOG</literal>, <literal>NOTICE</literal>,
+        <literal>WARNING</literal>, and <literal>ERROR</literal>.
         Each level includes all the levels that follow it.  The later the level,
         the fewer messages are sent.  The default is
         <literal>NOTICE</>.  Note that <literal>LOG</> has a different
         rank here than in <xref linkend="guc-log-min-messages">.
        </para>
+       <para>
+        <literal>INFO</literal> level messages are always sent to the client.
+       </para>
       </listitem>
      </varlistentry>