fix(medusa-fulfillment-manual): Missing retrieveDocuments override (#4221)

* adds missing retrieveDocuments override

* Create short-numbers-cheer.md

---------

Co-authored-by: Oliver Windall Juhl <59018053+olivermrbl@users.noreply.github.com>

packages/medusa-fulfillment-manual/src/services/manual-fulfillment.js

@@ -53,6 +53,10 @@ class ManualFulfillmentService extends FulfillmentService {
   cancelFulfillment() {
     return Promise.resolve({})
   }
+
+  retrieveDocuments() {
+    return Promise.resolve([])
+  }
 }
 
 export default ManualFulfillmentService