feat: add ja trans

Author: antfu

.vitepress/config.js

@@ -106,6 +106,10 @@ const Translations = [
     text: 'Ελληνικά',
     link: 'https://el.sli.dev{{pathname}}',
   },
+  {
+    text: '日本語',
+    link: 'https://ja.sli.dev{{pathname}}',
+  },
 ]
 
 const Customizations = [

README.md

@@ -15,6 +15,7 @@ Documentation for [Slidev](https://github.com/slidevjs/slidev)
 | Deutsch | [docs-de](https://github.com/slidevjs/docs-de) | [de.sli.dev](https://de.sli.dev) | [@fabiankachlock](https://github.com/fabiankachlock) |
 | Português (BR) | [docs-br](https://github.com/slidevjs/docs-br) | [br.sli.dev](https://br.sli.dev) | [@luisfelipesdn12](https://github.com/luisfelipesdn12) |
 | Ελληνικά | [docs-el](https://github.com/slidevjs/docs-el) | [el.sli.dev](https://el.sli.dev) | [@GeopJr](https://github.com/GeopJr) |
+| 日本語 | [docs-ja](https://github.com/slidevjs/docs-el) | [ja.sli.dev](https://ja.sli.dev) | [@IkumaTadokoro](https://github.com/IkumaTadokoro) |
 
 ## Start Server Locally