Fix subcommand detection when subcommand used with positional arguments. When there is only one valid subcommand passed, `ArgList::getSubCommand()` should return the correct subcommand even there are other positionals passed.
Fix subcommand detection when subcommand used with positional arguments. When there is only one valid subcommand passed, `ArgList::getSubCommand()` should return the correct subcommand even there are other positionals passed.