Make deadly reace return an abortable promise (types)

src/index.ts

@@ -142,7 +142,7 @@ export default class AbortablePromise<T> implements Promise<T | null> {
   static deadlyRace<L>(
     promises: AbortablePromise<L>[],
     should_kill_others: (arg: L) => Promise<boolean> = async () => true
-  ): Promise<L> {
+  ): AbortablePromise<L> {
     return new AbortablePromise(async function* (await_or_abort) {
       return await_or_abort(
         new Promise((resolve, _) => {