Fix occcontrol command help string

kestrel/src/shell.c

@@ -111,7 +111,7 @@ static void print_kestrel_pwmcontrol_command_usage(const struct shell *shell, ch
 }
 
 static void print_kestrel_occcontrol_command_usage(const struct shell *shell, char* command_name) {
-	shell_print(shell, "Usage: %s [detect]", command_name);
+	shell_print(shell, "Usage: %s [poll]", command_name);
 }
 
 static int kestrel_shell_cmd_utility(const struct shell *shell, size_t argc, char **argv)