fix general help command

src/lib66/exec/ssexec_help.c

@@ -55,7 +55,10 @@ char const *help_66 =
 "   init: initiate to scandir all services marked enabled at tree\n"
 "   parse: parse the service frontend file\n"
 "   scandir: manage scandir\n"
-"   boot: boot the system with 66\n"
+"   boot: boot the system\n"
+"   poweroff: poweroff the system\n"
+"   reboot: reboot the system\n"
+"   halt: halt the system\n"
 "   version: display 66 version\n"
 "\n"
 "Use '66 <command> -h' to see command options\n"