Fix outdated --help message for postgres -f

This option switch supports a total of 8 values, as told by
set_plan_disabling_options() and the documentation, but this was not
reflected in the output generated by --help.

Author: Junwang Zhao
Discussion: https://postgr.es/m/CAEG8a3+pT3cWzyjzKs184L1XMNm8NDnoJLiSjAYSO7XqpRh_vA@mail.gmail.com
Backpatch-through: 10

Author: michaelpq

src/backend/main/main.c

@@ -373,7 +373,7 @@ help(const char *progname)
 	printf(_("  -?, --help         show this help, then exit\n"));
 
 	printf(_("\nDeveloper options:\n"));
-	printf(_("  -f s|i|n|m|h       forbid use of some plan types\n"));
+	printf(_("  -f s|i|o|b|t|n|m|h forbid use of some plan types\n"));
 	printf(_("  -n                 do not reinitialize shared memory after abnormal exit\n"));
 	printf(_("  -O                 allow system table structure changes\n"));
 	printf(_("  -P                 disable system indexes\n"));