Fix some inconsistencies with GUC categories

This commit addresses a few things around GUCs:
- The TCP-related parameters (the four tcp_keepalives_* and
client_connection_check_interval are listed in postgresql.conf.sample in
a subsection called "TCP settings" of "CONNECTIONS AND AUTHENTICATION",
but they did not have their own group name in guc.c.
- enable_group_by_reordering, stats_fetch_consistency and
recovery_prefetch had an inconsistent description, missing a dot at the
end.
- In postgresql.conf.sample, "Process title" should not have a section
of its own, but it should be a subsection of "REPORTING AND LOGGING".

This impacts the contents of pg_settings, which could be seen as a
compatibility break, so no backpatch is done.  This is similar to the
cleanup done in a55a984.

Author: Shinya Kato
Discussion: https://postgr.es/m/5e0c9c608624eafbba910c344282cb14@oss.nttdata.com

doc/src/sgml/config.sgml

@@ -896,6 +896,13 @@ include_dir 'conf.d'
        </para>
       </listitem>
      </varlistentry>
+     </variablelist>
+     </sect2>
+
+     <sect2 id="runtime-config-tcp-settings">
+     <title>TCP Settings</title>
+
+     <variablelist>
 
      <varlistentry id="guc-tcp-keepalives-idle" xreflabel="tcp_keepalives_idle">
       <term><varname>tcp_keepalives_idle</varname> (<type>integer</type>)

src/backend/utils/misc/guc.c

@@ -778,6 +778,8 @@ const char *const config_group_names[] =
 	gettext_noop("File Locations"),
 	/* CONN_AUTH_SETTINGS */
 	gettext_noop("Connections and Authentication / Connection Settings"),
+	/* CONN_AUTH_TCP */
+	gettext_noop("Connections and Authentication / TCP Settings"),
 	/* CONN_AUTH_AUTH */
 	gettext_noop("Connections and Authentication / Authentication"),
 	/* CONN_AUTH_SSL */
@@ -1216,7 +1218,7 @@ static struct config_bool ConfigureNamesBool[] =
 	},
 	{
 		{"enable_group_by_reordering", PGC_USERSET, QUERY_TUNING_METHOD,
-			gettext_noop("enable reordering of GROUP BY key"),
+			gettext_noop("Enable reordering of GROUP BY key."),
 			NULL,
 			GUC_EXPLAIN
 		},
@@ -3460,7 +3462,7 @@ static struct config_int ConfigureNamesInt[] =
 	},
 
 	{
-		{"tcp_keepalives_idle", PGC_USERSET, CONN_AUTH_SETTINGS,
+		{"tcp_keepalives_idle", PGC_USERSET, CONN_AUTH_TCP,
 			gettext_noop("Time between issuing TCP keepalives."),
 			gettext_noop("A value of 0 uses the system default."),
 			GUC_UNIT_S
@@ -3471,7 +3473,7 @@ static struct config_int ConfigureNamesInt[] =
 	},
 
 	{
-		{"tcp_keepalives_interval", PGC_USERSET, CONN_AUTH_SETTINGS,
+		{"tcp_keepalives_interval", PGC_USERSET, CONN_AUTH_TCP,
 			gettext_noop("Time between TCP keepalive retransmits."),
 			gettext_noop("A value of 0 uses the system default."),
 			GUC_UNIT_S
@@ -3493,7 +3495,7 @@ static struct config_int ConfigureNamesInt[] =
 	},
 
 	{
-		{"tcp_keepalives_count", PGC_USERSET, CONN_AUTH_SETTINGS,
+		{"tcp_keepalives_count", PGC_USERSET, CONN_AUTH_TCP,
 			gettext_noop("Maximum number of TCP keepalive retransmits."),
 			gettext_noop("This controls the number of consecutive keepalive retransmits that can be "
 						 "lost before a connection is considered dead. A value of 0 uses the "
@@ -3595,7 +3597,7 @@ static struct config_int ConfigureNamesInt[] =
 	},
 
 	{
-		{"tcp_user_timeout", PGC_USERSET, CONN_AUTH_SETTINGS,
+		{"tcp_user_timeout", PGC_USERSET, CONN_AUTH_TCP,
 			gettext_noop("TCP user timeout."),
 			gettext_noop("A value of 0 uses the system default."),
 			GUC_UNIT_MS
@@ -3640,7 +3642,7 @@ static struct config_int ConfigureNamesInt[] =
 	},
 
 	{
-		{"client_connection_check_interval", PGC_USERSET, CONN_AUTH_SETTINGS,
+		{"client_connection_check_interval", PGC_USERSET, CONN_AUTH_TCP,
 			gettext_noop("Sets the time interval between checks for disconnection while running queries."),
 			NULL,
 			GUC_UNIT_MS
@@ -4953,7 +4955,7 @@ static struct config_enum ConfigureNamesEnum[] =
 
 	{
 		{"stats_fetch_consistency", PGC_USERSET, STATS_CUMULATIVE,
-			gettext_noop("Sets the consistency of accesses to statistics data"),
+			gettext_noop("Sets the consistency of accesses to statistics data."),
 			NULL
 		},
 		&pgstat_fetch_consistency,
@@ -5044,7 +5046,7 @@ static struct config_enum ConfigureNamesEnum[] =
 
 	{
 		{"recovery_prefetch", PGC_SIGHUP, WAL_RECOVERY,
-			gettext_noop("Prefetch referenced blocks during recovery"),
+			gettext_noop("Prefetch referenced blocks during recovery."),
 			gettext_noop("Look ahead in the WAL to find references to uncached data.")
 		},
 		&recovery_prefetch,

src/backend/utils/misc/postgresql.conf.sample

@@ -597,10 +597,7 @@
 					# -1 disables, 0 logs all temp files
 #log_timezone = 'GMT'
 
-
+# - Process Title -
-#------------------------------------------------------------------------------
-# PROCESS TITLE
-#------------------------------------------------------------------------------
 
 #cluster_name = ''			# added to process titles if nonempty
 					# (change requires restart)

src/include/utils/guc_tables.h

@@ -56,6 +56,7 @@ enum config_group
 	UNGROUPED,					/* use for options not shown in pg_settings */
 	FILE_LOCATIONS,
 	CONN_AUTH_SETTINGS,
+	CONN_AUTH_TCP,
 	CONN_AUTH_AUTH,
 	CONN_AUTH_SSL,
 	RESOURCES_MEM,