[doc] fix doc

Author: vimior

doc/api/xarm_api.md

@@ -2379,7 +2379,7 @@ xArm-Python-SDK API Documentation (V1.17.3): class XArmAPI in module xarm.wrappe
 > Note:  
 >     1. only available if firmware_version >= 2.7.110  
 >     2. after it is turned on, the position/speed/current information of the external device will be reported through port 30000  
->     3. once an error occurs, you need to restart to monitor  
+>     3. once an error occurs, you need to re call to monitor  
 >   
 > :param dev_type: the type of the external device  
 >     0: Turn off monitoring  

xarm/wrapper/xarm_api.py

@@ -4554,7 +4554,7 @@ def set_external_device_monitor_params(self, dev_type, frequency):
         Note:
             1. only available if firmware_version >= 2.7.110
             2. after it is turned on, the position/speed/current information of the external device will be reported through port 30000
-            3. once an error occurs, you need to restart to monitor
+            3. once an error occurs, you need to re call to monitor
 
         :param dev_type: the type of the external device
             0: Turn off monitoring