TS errors if model methods are not async

[z1haze]

According to the docs model methods are supposed to support either sync or async, but in practice when I attempted to, for example, write the generateRefreshToken in a synchronous function, typescript errors because it isn'y async. So i peaked into the interface that the source validates against, and all of the methods are written to return a promise.

Documentation stating that they can be sync (supposedly)

Version >=5.x: Callback support has been removed! Each model function supports either sync or async (Promise or async function) return values.

Source showing it expects it to return a promise

generateRefreshToken?(client: Client, user: User, scope: string[]): Promise<string>;