[IMP] index: export batched utility function

'batched' will be used in odoo/o-spreadsheet.
There's also a copied version (slightly modified) in odoo/odoo.

It shows it could be useful outside owl.

src/runtime/index.ts

@@ -41,7 +41,7 @@ export { useComponent, useState } from "./component_node";
 export { status } from "./status";
 export { reactive, markRaw, toRaw } from "./reactivity";
 export { useEffect, useEnv, useExternalListener, useRef, useChildSubEnv, useSubEnv } from "./hooks";
-export { EventBus, whenReady, loadFile, markup } from "./utils";
+export { batched, EventBus, whenReady, loadFile, markup } from "./utils";
 export {
   onWillStart,
   onMounted,