fix: update documentation for POST /orgs/{org}/migrations (#512)

Author: octokitbot

docs/migrations/startForOrg.md

@@ -75,6 +75,8 @@ Indicates whether this should only include organization metadata (repositories a
 </td></tr>
 <tr><td>exclude</td><td>no</td><td>
 
+Exclude related items from being returned in the response in order to improve performance of the request. The array can include any of: `"repositories"`.
+
 </td></tr>
   </tbody>
 </table>

scripts/update-endpoints/generated/endpoints.json

@@ -28384,7 +28384,7 @@
       },
       {
         "name": "exclude",
-        "description": "",
+        "description": "Exclude related items from being returned in the response in order to improve performance of the request. The array can include any of: `\"repositories\"`.",
         "in": "BODY",
         "type": "string[]",
         "required": false,