Remove an incorrect plural in docs/guides/using_items.mdx (#75)

Author: Benjamin-Loison

docs/guides/using_items.mdx

@@ -662,7 +662,7 @@ const item = await itemManager.fetch(itemUid, { stoken });
 ```python
 item = item_mgr.fetch(item_uid)
 
-# Can optionally pass stoken to only return the items if changed:
+# Can optionally pass stoken to only return the item if changed:
 item = item_mgr.fetch(item_uid, FetchOptions().stoken(stoken))
 ```