Merge pull request #5503 from whj4674672/notes

update notes

include/rtdef.h

@@ -636,7 +636,7 @@ struct rt_thread
 
 #ifdef RT_USING_SMP
     rt_uint8_t  bind_cpu;                               /**< thread is bind to cpu */
-    rt_uint8_t  oncpu;                                  /**< process on cpu` */
+    rt_uint8_t  oncpu;                                  /**< process on cpu */
 
     rt_uint16_t scheduler_lock_nest;                    /**< scheduler lock count */
     rt_uint16_t cpus_lock_nest;                         /**< cpus lock count */