docs: use mappedBy property for all relationship types (#12973)

www/apps/resources/app/recipes/marketplace/examples/restaurant-delivery/page.mdx

@@ -122,7 +122,9 @@ export const Restaurant = model.define("restaurant", {
   email: model.text(),
   address: model.text(),
   image_url: model.text().nullable(),
-  admins: model.hasMany(() => RestaurantAdmin),
+  admins: model.hasMany(() => RestaurantAdmin, {
+    mappedBy: "restaurant",
+  }),
 })
 ```
 

www/apps/resources/app/recipes/marketplace/examples/vendors/page.mdx

@@ -135,7 +135,9 @@ const Vendor = model.define("vendor", {
   handle: model.text().unique(),
   name: model.text(),
   logo: model.text().nullable(),
-  admins: model.hasMany(() => VendorAdmin),
+  admins: model.hasMany(() => VendorAdmin, {
+    mappedBy: "vendor",
+  }),
 })
 
 export default Vendor