Wrap code in 03.2.md (en) with code block syntax

en/03.2.md

@@ -4,6 +4,7 @@ We've discussed that web applications are based on the HTTP protocol, and Go pro
 
 ## Use http package setup a web server
 
+```go
 	package main
 
 	import (
@@ -33,6 +34,7 @@ We've discussed that web applications are based on the HTTP protocol, and Go pro
         	log.Fatal("ListenAndServe: ", err)
     	}
 	}
+```
 	
 After we execute the above code, the server begins listening to port 9090 in local host.