Allow async preHandler hooks on RouteShorthandOptions

[SlyryD]

Description

In response to issue #5086, where I mentioned that the hookRunner function can handle async preHandler hooks, I added types to route.d.ts to allow async preHandler hooks. This change makes it clear that you want either a callback-based hook that returns void or an async hook that returns a Promise -- using an async hook with a callback is problematic and not handled properly by hookRunner. This change can probably be applied to the other hooks in RouteShorthandOptions, but I scoped it just to the preHandler hook, which I tested locally. In fact, there are already tests in route.test-d.ts that validate async hooks.

Checklist

• run npm run test and npm run benchmark
• tests and/or benchmarks are included
• documentation is changed or added
• commit message and code follows the Developer's Certification of Origin
  and the Code of conduct

[SlyryD]

TypeScript isn't able to infer the parameter types with my changes. I'll mark this as Draft for now.

[bienzaaron]

The same type update was attempted in #4655, but then reverted due to this issue #4705 (same thing you're describing)

I opened #5147 which allows async hooks without breaking the inference on parameters

[SlyryD]

Closed in favor of #5147