Merge pull request #205 from flavio-b/patch-2

Correct event.detail properties of `turbo:submit-end`

_source/reference/events.md

@@ -155,12 +155,12 @@ Fires during a form submission. Access the [FormSubmission][] object with `event
 
 Fires after the form submission-initiated network request completes. Access the [FormSubmission][] object with `event.detail.formSubmission` along with the properties included within `event.detail`.
 
-| `event.detail` property   | Type                          | Description
-|---------------------------|-------------------------------|------------
-| `formSubmission`          | [FormSubmission][]            | the `<form>` element submission
-| `success`                 | `boolean`                     | a `boolean` representing the request's success
-| `fetchResponse`           | [FetchResponse][] \| `null`   | present when `success: true`, `null` when `success: false`
-| `error`                   | [Error][] or `null`           | `null` when `success: true`, present when `success: false`
+| `event.detail` property   | Type                             | Description
+|---------------------------|----------------------------------|------------
+| `formSubmission`          | [FormSubmission][]               | the `<form>` element submission
+| `success`                 | `boolean`                        | a `boolean` representing the request's success
+| `fetchResponse`           | [FetchResponse][] \| `undefined` | present when a response is received, even if `success: false`. `undefined` if the request errored before a response was received
+| `error`                   | [Error][] \| `undefined`         | `undefined` unless an actual fetch error occurs (e.g., network issues)
 
 [Error]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Errors
 [FormSubmission]: /reference/drive#formsubmission