add placeholder of the i18n config for translations (#2028)

Author: Jinjiang

.vitepress/config.ts

@@ -6,7 +6,7 @@ import baseConfig from '@vue/theme/config'
 import { headerPlugin } from './headerMdPlugin'
 import { jobsPlugin } from './jobsMdPlugin'
 
-const nav = [
+const nav: ThemeConfig['nav'] = [
   {
     text: 'Docs',
     activeMatch: `^/(guide|style-guide|cookbook|examples)/`,
@@ -123,7 +123,7 @@ const nav = [
   }
 ]
 
-export const sidebar = {
+export const sidebar: ThemeConfig['sidebar'] = {
   '/guide/': [
     {
       text: 'Getting Started',
@@ -551,6 +551,10 @@ export const sidebar = {
   ]
 }
 
+// Placeholder of the i18n config for @vuejs-translations.
+// const i18n: ThemeConfig['i18n'] = {
+// }
+
 export default defineConfigWithTheme<ThemeConfig>({
   extends: baseConfig,
 
@@ -601,6 +605,8 @@ export default defineConfigWithTheme<ThemeConfig>({
   themeConfig: {
     nav,
     sidebar,
+    // Placeholder of the i18n config for @vuejs-translations.
+    // i18n,
 
     algolia: {
       indexName: 'vuejs',