chore: move to eslint flat config

resolve #1436

vitejs/vite@8f16765 の反映です。

.vitepress/buildEnd.config.ts

@@ -1,12 +1,13 @@
-import path from 'path'
-import { writeFileSync } from 'fs'
+import path from 'node:path'
+import { writeFileSync } from 'node:fs'
 import { Feed } from 'feed'
-import { createContentLoader, type SiteConfig } from 'vitepress'
+import type { SiteConfig } from 'vitepress'
+import { createContentLoader } from 'vitepress'
 
 const siteUrl = 'https://vitejs.dev'
 const blogUrl = `${siteUrl}/blog`
 
-export const buildEnd = async (config: SiteConfig) => {
+export const buildEnd = async (config: SiteConfig): Promise<void> => {
   const feed = new Feed({
     title: 'Vite',
     description: 'Next Generation Frontend Tooling',

.vitepress/config.ts

@@ -1,4 +1,5 @@
-import { defineConfig, DefaultTheme } from 'vitepress'
+import type { DefaultTheme } from 'vitepress'
+import { defineConfig } from 'vitepress'
 import { transformerTwoslash } from '@shikijs/vitepress-twoslash'
 import { buildEnd } from './buildEnd.config'
 

.vitepress/theme/composables/sponsor.ts

@@ -1,4 +1,4 @@
-import { ref, onMounted, onUnmounted } from 'vue'
+import { onMounted, onUnmounted, ref } from 'vue'
 
 interface Sponsors {
   special: Sponsor[]