Update serving_en.md

doc/doc_en/serving_en.md

@@ -157,23 +157,18 @@ If you need to modify the service logic, the following steps are generally requi
 - 1. Stop service
 ```shell
 hub serving stop --port/-p XXXX
-```  
-
+```
 - 2. Modify the code in the corresponding files, like `module.py` and `params.py`, according to the actual needs.  
 For example, if you need to replace the model used by the deployed service, you need to modify model path parameters `det_model_dir` and `rec_model_dir` in `params.py`. Of course, other related parameters may need to be modified at the same time. Please modify and debug according to the actual situation. It is suggested to run `module.py` directly for debugging after modification before starting the service test.  
-
 - 3. Uninstall old service module
 ```shell
 hub uninstall ocr_system
 ```
-
 - 4. Install modified service module
 ```shell
 hub install deploy/hubserving/ocr_system/
-```  
-
+```
 - 5. Restart service
 ```shell
 hub serving start -m ocr_system
-```  
-
+```