docs: integrate @nuxt/ui-pro (#739)

Co-authored-by: Pooya Parsa <pooya@pi0.io>
Co-authored-by: Florent Delerue <florentdelerue@hotmail.com>
Co-authored-by: Sébastien Chopin <seb@nuxt.com>

docs/pages/[...slug].vue

@@ -7,7 +7,7 @@
 
       <hr v-if="surround?.length">
 
-      <UDocsSurround :surround="(surround as ParsedContent[])" />
+      <UDocsSurround :surround="surround" />
     </UPageBody>
 
     <template v-if="page.body?.toc?.links?.length" #right>
@@ -26,7 +26,6 @@
 
 <script setup lang="ts">
 import { withoutTrailingSlash } from 'ufo'
-import type { ParsedContent } from '@nuxt/content/dist/runtime/types'
 
 const route = useRoute()
 const { branch } = useContentSource()