fix(typings): allow async listener in typed events
fix(typings): allow async listener in typed events

So that:

```ts
socket.on("my-event", async () => {
  // ...
});
```

is valid under the @typescript-eslint/no-misused-promises rule.

Related: https://github.com/socketio/socket.io-client/issues/1486

socketio/socket.io,Automattic/socket.io,socketio/socket.io,mosoft521/socket.io,Automattic/socket.io,mosoft521/socket.io