fix docs code block formatting

docs/docs/38-authoring/21-services.md

@@ -10,8 +10,6 @@ When you are authoring the Acornfile for your application you can define cloud s
 
 Service attritibutes are accessed through the `@{}` syntax in the Acornfile. Here is a simple example of accessing the `address` attribute of a service named `db`. For complete service syntax see the [services](/100-reference/03-acornfile.md#services-consuming) section in the Acornfile reference.
 
-```acorn
-
 ```acorn
 // This service exposes an address and a secret
 services: db: {