chore(docs): Generated API Reference (#4783)

Co-authored-by: shahednasser <shahednasser@users.noreply.github.com>

www/api-reference/specs/admin/components/schemas/AdminPostInventoryItemsReq.yaml

@@ -1,5 +1,10 @@
 type: object
+required:
+  - variant_id
 properties:
+  variant_id:
+    description: The ID of the variant to create the inventory item for.
+    type: string
   sku:
     description: The unique SKU of the associated Product Variant.
     type: string

www/api-reference/specs/admin/paths/admin_inventory-items.yaml

@@ -152,7 +152,7 @@ get:
 post:
   operationId: PostInventoryItems
   summary: Create an Inventory Item
-  description: Create an Inventory Item.
+  description: Create an Inventory Item for a product variant.
   x-authenticated: true
   parameters:
     - in: query