feat: add danmuku plugin documentation and i18n setup guide

- Created a new documentation file for the danmuku plugin with code examples.
- Added a comprehensive guide for language settings (i18n) including default languages, importing languages, adding new languages, and modifying existing languages.
- Included code snippets for initializing the Artplayer with different language configurations.

docs/assets/example/websr.js

@@ -1,3 +1,4 @@
+// https://github.com/sb2702/websr
 // npm i artplayer-plugin-websr
 // import artplayerPluginWebsr from 'artplayer-plugin-websr';
 
@@ -7,6 +8,7 @@ var art = new Artplayer({
     fullscreenWeb: true,
     plugins: [
         artplayerPluginWebsr({
+            videoScale: 2,
             networkSize: 'medium',
             weightsBaseUrl: '/assets/websr/weights',
             workerUrl: '/assets/websr/worker/main.js',