Update serving_en.md

doc/doc_en/serving_en.md

@@ -52,7 +52,6 @@ Or, install the 2-stage series service module:
 ```shell
 hub install deploy/hubserving/ocr_system/
 ```
-
 * On Windows platform, the examples are as follows.
 
 Install the detection service module:
@@ -66,7 +65,7 @@ hub install deploy\hubserving\ocr_rec\
 Or, install the 2-stage series service module:
 ```shell
 hub install deploy\hubserving\ocr_system\
-
+```
 
 ### 3. Start service
 #### Way 1. Start with command line parameters (CPU only)