Fix tsconfigs, IDisposable, and add comments

src/browser/Terminal.ts

@@ -883,12 +883,13 @@ export class Terminal extends CoreTerminal implements ITerminal {
     return this.linkifier2.registerLinkProvider(linkProvider);
   }
 
-  public registerClipboardProvider(provider: IClipboardProvider): void {
+  public registerClipboardProvider(provider: IClipboardProvider): IDisposable {
     this._clipboardProvider = provider;
-  }
-
-  public deregisterClipboardProvider(): void {
-    this._clipboardProvider = undefined;
+    return {
+      dispose: () => {
+        this._clipboardProvider = undefined;
+      }
+    };
   }
 
   public registerCharacterJoiner(handler: CharacterJoinerHandler): number {

src/browser/TestUtils.test.ts

@@ -104,10 +104,7 @@ export class MockTerminal implements ITerminal {
   public registerDecoration(decorationOptions: IDecorationOptions): IDecoration | undefined {
     throw new Error('Method not implemented.');
   }
-  public registerClipboardProvider(provider: IClipboardProvider): void {
-    throw new Error('Method not implemented.');
-  }
-  public deregisterClipboardProvider(): void {
+  public registerClipboardProvider(provider: IClipboardProvider): IDisposable {
     throw new Error('Method not implemented.');
   }
   public hasSelection(): boolean {

src/browser/public/Terminal.ts

@@ -168,11 +168,8 @@ export class Terminal extends Disposable implements ITerminalApi {
     this._verifyPositiveIntegers(decorationOptions.x ?? 0, decorationOptions.width ?? 0, decorationOptions.height ?? 0);
     return this._core.registerDecoration(decorationOptions);
   }
-  public registerClipboardProvider(provider: IClipboardProvider): void {
-    this._core.registerClipboardProvider(provider);
-  }
-  public deregisterClipboardProvider(): void {
-    this._core.deregisterClipboardProvider();
+  public registerClipboardProvider(provider: IClipboardProvider): IDisposable {
+    return this._core.registerClipboardProvider(provider);
   }
   public hasSelection(): boolean {
     return this._core.hasSelection();