chore(docs): Generated API Reference (#4706)

Co-authored-by: olivermrbl <olivermrbl@users.noreply.github.com>
Co-authored-by: Shahed Nasser <shahednasser@gmail.com>

docs/api/admin/components/schemas/AdminPostDraftOrdersDraftOrderLineItemsReq.yaml

@@ -3,18 +3,26 @@ required:
   - quantity
 properties:
   variant_id:
-    description: The ID of the Product Variant to generate the Line Item from.
+    description: >-
+      The ID of the Product Variant associated with the line item. If the line
+      item is custom, the `variant_id` should be omitted.
     type: string
   unit_price:
-    description: The potential custom price of the item.
+    description: >-
+      The custom price of the line item. If a `variant_id` is supplied, the
+      price provided here will override the variant's price.
     type: integer
   title:
-    description: The potential custom title of the item.
+    description: The title of the line item if `variant_id` is not provided.
     type: string
     default: Custom item
   quantity:
-    description: The quantity of the Line Item.
+    description: The quantity of the line item.
     type: integer
   metadata:
     description: The optional key-value map with additional details about the Line Item.
     type: object
+    externalDocs:
+      description: Learn about the metadata attribute, and how to delete and update it.
+      url: >-
+        https://docs.medusajs.com/development/entities/overview#metadata-attribute