Add french language (#460)

* Create fr.json

* Update index.js

* Update i18n.d.ts

* Update option.md

* Update option.md

* Update artplayer.d.ts

packages/artplayer-vitepress/docs/start/option.md

@@ -1058,7 +1058,7 @@ var art = new Artplayer({
 -   Type: `String`
 -   Default: `navigator.language.toLowerCase()`
 
-默认显示语言，目前支持：`en`, `zh-cn`, `zh-tw`, `cs`, `pl`, `es`, `fa`
+默认显示语言，目前支持：`en`, `zh-cn`, `zh-tw`, `cs`, `pl`, `es`, `fa`, `fr`
 
 <div className="run-code">▶ Run Code</div>
 
@@ -1211,4 +1211,4 @@ var art = new Artplayer({
     url: '/assets/sample/video.mp4',
     airplay: true,
 });
-```
+```