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

www/apps/docs/content/references/js-client/classes/PaymentMethodsResource.mdx

@@ -14,12 +14,12 @@ All methods in this class require [customer authentication](AuthResource.mdx#aut
 
 ## Methods
 
-#### list
+### list
 
 Retrieve the logged-in customer's saved payment methods. This method only works with payment providers created with the deprecated Payment Service interface.
 The payment methods are saved using the Payment Service's third-party service, and not on the Medusa backend. So, they're retrieved from the third-party service.
 
-##### Example
+#### Example
 
 ```ts
 import Medusa from "@medusajs/medusa-js"
@@ -30,7 +30,7 @@ medusa.customers.paymentMethods.list().then(({ payment_methods }) => {
 })
 ```
 
-##### Parameters
+#### Parameters
 
 <ParameterTypes parameters={[
   {
@@ -44,7 +44,7 @@ medusa.customers.paymentMethods.list().then(({ payment_methods }) => {
   }
 ]} />
 
-##### Returns
+#### Returns
 
 <ParameterTypes parameters={[
   {