feat: add danmuku plugin documentation and i18n setup instructions

- Created a new documentation file for the danmuku plugin with code examples.
- Added comprehensive language settings documentation, including default languages, importing languages, adding new languages, and modifying existing languages.
- Updated the i18n setup examples to reflect the latest changes in language handling.

docs/assets/ts/artplayer-plugin-dash-control.d.ts

@@ -1,8 +1,3 @@
-import type Artplayer from 'artplayer'
-
-export = artplayerPluginDashControl
-export as namespace artplayerPluginDashControl;
-
 interface Config {
   control?: boolean
   setting?: boolean
@@ -15,3 +10,8 @@ declare const artplayerPluginDashControl: (option: { quality?: Config, audio?: C
   name: 'artplayerPluginDashControl'
   update: () => void
 }
+
+export default artplayerPluginDashControl
+
+export = artplayerPluginDashControl;
+export as namespace artplayerPluginDashControl;