docs: TSDoc + reference of fulfillment service (#5761)

www/apps/docs/content/references/services/classes/Order.mdx

@@ -8,14 +8,14 @@ import ParameterTypes from "@site/src/components/ParameterTypes"
 
 An order is a purchase made by a customer. It holds details about payment and fulfillment of the order. An order may also be created from a draft order, which is created by an admin user.
 
-## Constructors
-
-#### constructor
+## constructor
 
 `**new Order**()`
 
 An order is a purchase made by a customer. It holds details about payment and fulfillment of the order. An order may also be created from a draft order, which is created by an admin user.
 
+___
+
 ## Properties
 
 <ParameterTypes parameters={[
@@ -534,13 +534,15 @@ An order is a purchase made by a customer. It holds details about payment and fu
   }
 ]} />
 
+___
+
 ## Methods
 
-#### beforeInsert
+### beforeInsert
 
 `Private **beforeInsert**(): Promise&#60;void&#62;`
 
-##### Returns
+#### Returns
 
 Promise&#60;void&#62;