chore: annotate `each_array` return value (#18325)

tiny self-mergeable change extracted from #18035 — just turns
`each_array` from a `Derived<any[]>` to a `Derived<V[]>`

packages/svelte/src/internal/client/dom/blocks/each.js

@@ -203,7 +203,9 @@ export function each(node, flags, get_collection, get_key, render_fn, fallback_f
 	var each_array = derived_safe_equal(() => {
 		var collection = get_collection();
 
-		return is_array(collection) ? collection : collection == null ? [] : array_from(collection);
+		return /** @type {V[]} */ (
+			is_array(collection) ? collection : collection == null ? [] : array_from(collection)
+		);
 	});
 
 	if (DEV) {