[HUST_CSE] add doxygen missing @brief (#7368)

src/clock.c

@@ -40,7 +40,7 @@ static void (*rt_tick_hook)(void);
 /**@{*/
 
 /**
- * This function will set a hook function, which will be invoked when tick increase
+ * @brief This function will set a hook function, which will be invoked when tick increase
  *
  *
  * @param hook the hook function
@@ -176,4 +176,3 @@ rt_weak rt_tick_t rt_tick_get_millisecond(void)
 }
 
 /**@}*/
-