Add missing options to pg_regress help() output

A few command line options accepted by pg_regress were not being output
by help(), including --help itself. Add that one, as well as --version
and --bindir, and the corresponding short options for the first two.

We could consider this for backpatching, but it did not seem worthwhile
and no one else advocated for it, so apply only to master for now.

Author: Joe Conway
Reviewed-By: Tom Lane
Discussion: https://postgr.es/m/dd519469-06d7-2662-83ef-c926f6c4f0f1%40joeconway.com

src/test/regress/pg_regress.c

@@ -2004,12 +2004,15 @@ help(void)
 	printf(_("Usage:\n  %s [OPTION]... [EXTRA-TEST]...\n"), progname);
 	printf(_("\n"));
 	printf(_("Options:\n"));
+	printf(_("      --bindir=BINPATH          use BINPATH for programs that are run;\n"));
+	printf(_("                                if empty, use PATH from the environment\n"));
 	printf(_("      --config-auth=DATADIR     update authentication settings for DATADIR\n"));
 	printf(_("      --create-role=ROLE        create the specified role before testing\n"));
 	printf(_("      --dbname=DB               use database DB (default \"regression\")\n"));
 	printf(_("      --debug                   turn on debug mode in programs that are run\n"));
 	printf(_("      --dlpath=DIR              look for dynamic libraries in DIR\n"));
 	printf(_("      --encoding=ENCODING       use ENCODING as the encoding\n"));
+	printf(_("  -h, --help                    show this help, then exit\n"));
 	printf(_("      --inputdir=DIR            take input files from DIR (default \".\")\n"));
 	printf(_("      --launcher=CMD            use CMD as launcher of psql\n"));
 	printf(_("      --load-extension=EXT      load the named extension before running the\n"));
@@ -2025,6 +2028,7 @@ help(void)
 	printf(_("                                (can be used multiple times to concatenate)\n"));
 	printf(_("      --temp-instance=DIR       create a temporary instance in DIR\n"));
 	printf(_("      --use-existing            use an existing installation\n"));
+	printf(_("  -V, --version                 output version information, then exit\n"));
 	printf(_("\n"));
 	printf(_("Options for \"temp-instance\" mode:\n"));
 	printf(_("      --no-locale               use C locale\n"));