1.msh优化，简化使用流程。

2.新增回显命令。

include/components/mr_msh.h

@@ -59,24 +59,15 @@ struct mr_msh_cmd
 #define MR_MSH_GET_ARG(index) \
     (((index) < (argc)) ? (((const char **)(argv))[index]) : MR_NULL)
 
-/**
- * @brief This macro function prints a formatted string.
- *
- * @param fmt The format string.
- * @param ... The arguments.
- */
-#define mr_msh_printf(fmt, ...) mr_printf(fmt, ##__VA_ARGS__)
-
 /**
  * @addtogroup Msh.
  * @{
  */
-void mr_msh_recv_char(char c);
+int mr_msh_printf_output(const char *buf, size_t size);
+int mr_msh_input(char *c);
+int mr_msh_printf(const char *fmt, ...);
+void mr_msh_handle(void);
 /** @} */
-#else
-#define MR_MSH_EXPORT(name, fn, help, level)
-#define MR_MSH_CMD_EXPORT(name, fn, help)
-#define mr_msh_printf(...)
 #endif /* MR_USING_MSH */
 
 #ifdef __cplusplus