Update toStringTag in CancellablePromise

Author: mstosio

src/templates/core/CancelablePromise.hbs

@@ -21,8 +21,6 @@ export interface OnCancel {
 }
 
 export class CancelablePromise<T> implements Promise<T> {
-	readonly [Symbol.toStringTag]: string;
-
 	#isResolved: boolean;
 	#isRejected: boolean;
 	#isCancelled: boolean;
@@ -85,6 +83,10 @@ export class CancelablePromise<T> implements Promise<T> {
 		});
 	}
 
+	 get [Symbol.toStringTag]() {
+            return "Cancellable Promise";
+     }
+
 	public then<TResult1 = T, TResult2 = never>(
 		onFulfilled?: ((value: T) => TResult1 | PromiseLike<TResult1>) | null,
 		onRejected?: ((reason: any) => TResult2 | PromiseLike<TResult2>) | null