Add ts to demo

packages/artplayer/types/artplayer.d.ts

@@ -1,4 +1,5 @@
 export = Artplayer;
+export as namespace Artplayer;
 
 interface Selector {
     default?: boolean;
@@ -29,7 +30,7 @@ interface Component {
     add(option: ComponentOption): HTMLElement;
 }
 
-type Plugin = (art: Artplayer) => any;
+type PluginFunction = (art: Artplayer) => any;
 type WhitelistFunction = (ua: string) => Boolean;
 type CustomType = (video: HTMLVideoElement, url: string, art: Artplayer) => any;
 type EventCallback = (event: Event) => any;
@@ -66,7 +67,7 @@ interface Option {
     localVideo?: boolean;
     localSubtitle?: boolean;
     useSSR?: boolean;
-    plugins?: Plugin[];
+    plugins?: PluginFunction[];
     whitelist?: (string | WhitelistFunction | RegExp)[];
     layers?: ComponentOption[];
     contextmenu?: ComponentOption[];
@@ -271,7 +272,7 @@ declare class Artplayer extends Player {
 
     readonly plugins: {
         readonly id: number;
-        add(plugin: Plugin): Artplayer['plugins'];
+        add(plugin: PluginFunction): Artplayer['plugins'];
     };
 
     readonly i18n: {