use event from xterm.js instead of own impl

addons/addon-progress/typings/addon-progress.d.ts

@@ -3,7 +3,7 @@
  * @license MIT
  */
 
-import { Terminal, ITerminalAddon, IDisposable } from '@xterm/xterm';
+import { Terminal, ITerminalAddon, IDisposable, IEvent } from '@xterm/xterm';
 import type { ProgressState } from '../src/ProgressAddon';
 
 declare module '@xterm/addon-progress' {
@@ -13,8 +13,7 @@ declare module '@xterm/addon-progress' {
     public activate(terminal: Terminal): void;
     public dispose(): void;
 
-    /** register progress handler */
-    public register(handler: ProgressHandler): IDisposable;
+    public readonly onChange: IEvent<IProgress>;
 
     /** getter / setter for current progress */
     public progress: IProgress;
@@ -25,7 +24,4 @@ declare module '@xterm/addon-progress' {
     state: ProgressState;
     value: number;
   }
-  
-  /** Progress handler type */
-  export type ProgressHandler = (state: ProgressState, value: number) => void;
 }