use cachedRead

lib/server.ts

@@ -1,5 +1,4 @@
 import path from 'path'
-import { promises  as fs } from 'fs'
 import {
   createServer as createViteServer,
   cachedRead,
@@ -44,7 +43,7 @@ const VitePressPlugin: Plugin = ({ app, root, watcher, resolver }) => {
   // hot reload .md files as .vue files
   watcher.on('change', async (file) => {
     if (file.endsWith('.md')) {
-      const content = await fs.readFile(file, 'utf-8')
+      const content = await cachedRead(null, file)
       watcher.handleVueReload(file, Date.now(), markdownToVue(content))
     }
   })