refactor: recreate extension exports

packages/extension-document/src/document.ts

@@ -1,13 +1,11 @@
 import { Node } from '@tiptap/core'
 
-const Document = Node.create({
+export const Document = Node.create({
   name: 'document',
   topNode: true,
   content: 'block+',
 })
 
-export default Document
-
 declare module '@tiptap/core' {
   interface AllExtensions {
     Document: typeof Document,