Sync svelte docs (#1308)

sync svelte docs

Co-authored-by: svelte-docs-bot[bot] <196124396+svelte-docs-bot[bot]@users.noreply.github.com>

Author: github-actions[bot]

apps/svelte.dev/content/docs/svelte/98-reference/20-svelte.md

@@ -239,7 +239,7 @@ property and can contain any type of data.
 The event dispatcher can be typed to narrow the allowed event names and the type of the `detail` argument:
 ```ts
 const dispatch = createEventDispatcher<{
- loaded: never; // does not take a detail argument
+ loaded: null; // does not take a detail argument
  change: string; // takes a detail argument of type string, which is required
  optional: number | null; // takes an optional detail argument of type number
 }>();