Remove Instance_ internal type

I can't type my code properly:

import { definePool, Pool, Instance } from 'prool';
...
  let instance: Instance;
  instance = await pool.start(1);

Type 'Instance_' is not assignable to type 'Instance'.
  Property 'create' is missing in type 'Instance_' but required in type '{ _internal: object | undefined; create(parameters?: { port?: number | undefined; } | undefined): Omit<Instance<object | undefined>, "create">; host: string; ... 6 more ...; stop(): Promise<...>; }'.

That's because

type Instance_ = Omit<Instance, 'create'>

Proposed solution: do not use Instance_, make create disabled at runtime instead of removing it on the type level. Alternatively, make it a static method.

Start by locating the Instance_ and Instance type definitions and the pool.start(1) entry point. Compare the public return type with the runtime API, then resolve whether create should remain on the type, be disabled at runtime, or become static; done means the example assigns successfully without exposing an unusable create method.