feat: add danmuku plugin documentation and i18n setup guide

- Created a new documentation file for the danmuku plugin with code examples.
- Added comprehensive i18n setup instructions, including default language settings, language imports, and examples for adding and modifying languages.
- Updated the structure and content of the i18n documentation to enhance clarity and usability.

packages/artplayer-vitepress/docs/en/start/i18n.md

@@ -26,14 +26,15 @@ var art = new Artplayer({
 
 ## Importing Languages
 
-Language files before packaging are located in: `artplayer/src/i18n/*.js`. You are welcome to add your language.
-Packaged language files are located at: `artplayer/dist/i18n/*.js`
+Language files before packaging are located in: `artplayer/src/i18n/*.js`. 
+
+Packaged language files are located at: `artplayer/dist/i18n/*.js`.
 
 ::: code-group
 
 ```js [import]
-import id from 'artplayer/dist/i18n/id.js';
-import zhTw from 'artplayer/dist/i18n/zh-tw.js';
+import id from 'artplayer/i18n/id';
+import zhTw from 'artplayer/i18n/zh-tw';
 
 var art = new Artplayer({
     container: '.artplayer-app',
@@ -80,7 +81,7 @@ var art = new Artplayer({
 ## Modify Language
 
 ```js
-import zhTw from 'artplayer/i18n/zh-tw.js';
+import zhTw from 'artplayer/i18n/zh-tw';
 
 var art = new Artplayer({
     container: '.artplayer-app',