improve dev server startup time

docs/src/demos/React/components/Editor.jsx

@@ -1,4 +1,4 @@
-import {
+import React, {
   useState, useRef, useEffect, createContext, useContext,
 } from 'react'
 import { Editor as Tiptap } from '@tiptap/core'

docs/src/demos/React/index.jsx

@@ -1,4 +1,4 @@
-import { useState } from 'react'
+import React, { useState } from 'react'
 import extensions from '@tiptap/starter-kit'
 import { useEditor, Editor } from './components/Editor'