Add support of TS type annotations on `ofetch.create`

Describe the feature

Hi everyone!

I really love using ofetch because it's very powerful and covers almost all use cases.

The one feature that is missing for me is type annotatations. I believe this could be automated using tools like openapi-typescript, which can generate TS-types based on OpenAPI specification.

So what I mean is:

// import types auto-generated from the OpenAPI spec
// they're generated by openapi-typescript
import type { paths } from './autogenerated-types/my-api';

const myApiFetch = ofetch.create<paths>(options)  // provide paths as generic to ofetch.create

// intellisense for request URL, method, body, etc.
myApiFetch('/endpoint', {
  method: 'POST',
  body: {}
})

The openapi-typescript has its own package called openapi-fetch with support of this feature, but since ofetch is great integrated into Nuxt 3, it would be very nice to also have this possibility here. And ofetch has more features than the openapi-fetch.

Additional information

• Would you be willing to help implement this feature?

Start by locating the TypeScript declarations and implementation of ofetch.create, then compare their current generic support with the example using generated OpenAPI paths types. Determine the intended typing scope and add tests for URL, method, and request-body inference. Done means the documented ofetch.create<paths>(options) usage provides the requested IntelliSense without breaking existing calls.