doc: Improve pg_restore help output

Add a note that some options can be specified multiple times to select
multiple objects to restore.  This replaces the somewhat confusing use
of plurals in the option descriptions themselves.

src/bin/pg_dump/pg_restore.c

@@ -446,17 +446,17 @@ usage(const char *progname)
 	printf(_("  -c, --clean                  clean (drop) database objects before recreating\n"));
 	printf(_("  -C, --create                 create the target database\n"));
 	printf(_("  -e, --exit-on-error          exit on error, default is to continue\n"));
-	printf(_("  -I, --index=NAME             restore named indexes\n"));
+	printf(_("  -I, --index=NAME             restore named index\n"));
 	printf(_("  -j, --jobs=NUM               use this many parallel jobs to restore\n"));
 	printf(_("  -L, --use-list=FILENAME      use table of contents from this file for\n"
 			 "                               selecting/ordering output\n"));
-	printf(_("  -n, --schema=NAME            restore only objects in these schemas\n"));
+	printf(_("  -n, --schema=NAME            restore only objects in this schema\n"));
 	printf(_("  -O, --no-owner               skip restoration of object ownership\n"));
-	printf(_("  -P, --function=NAME(args)    restore named functions\n"));
+	printf(_("  -P, --function=NAME(args)    restore named function\n"));
 	printf(_("  -s, --schema-only            restore only the schema, no data\n"));
 	printf(_("  -S, --superuser=NAME         superuser user name to use for disabling triggers\n"));
-	printf(_("  -t, --table=NAME             restore named tables\n"));
-	printf(_("  -T, --trigger=NAME           restore named triggers\n"));
+	printf(_("  -t, --table=NAME             restore named table\n"));
+	printf(_("  -T, --trigger=NAME           restore named trigger\n"));
 	printf(_("  -x, --no-privileges          skip restoration of access privileges (grant/revoke)\n"));
 	printf(_("  -1, --single-transaction     restore as a single transaction\n"));
 	printf(_("  --disable-triggers           disable triggers during data-only restore\n"));
@@ -465,7 +465,7 @@ usage(const char *progname)
 			 "                               created\n"));
 	printf(_("  --no-security-labels         do not restore security labels\n"));
 	printf(_("  --no-tablespaces             do not restore tablespace assignments\n"));
-	printf(_("  --section=SECTION            restore named sections (pre-data, data, or post-data)\n"));
+	printf(_("  --section=SECTION            restore named section (pre-data, data, or post-data)\n"));
 	printf(_("  --use-set-session-authorization\n"
 			 "                               use SET SESSION AUTHORIZATION commands instead of\n"
 			 "                               ALTER OWNER commands to set ownership\n"));
@@ -478,6 +478,9 @@ usage(const char *progname)
 	printf(_("  -W, --password           force password prompt (should happen automatically)\n"));
 	printf(_("  --role=ROLENAME          do SET ROLE before restore\n"));
 
+	printf(_("\n"
+			 "The options -I, -n, -P, -t, -T, and --section can be combined and specified\n"
+			 "multiple times to select multiple objects.\n"));
 	printf(_("\nIf no input file name is supplied, then standard input is used.\n\n"));
 	printf(_("Report bugs to <pgsql-bugs@postgresql.org>.\n"));
 }