Feature request: enforce generic types when passed to `ReactFireOptions`

Comienza buscando en los fuentes TypeScript la interfaz ReactFireOptions y las apariciones de {[key: string]: unknown}. Actualiza los tipos de opciones para que los genéricos explícitos restrinjan initialData y startWithValue, reemplaza las firmas de índice aplicables por Record<string, unknown> y verifica que los valores genéricos que no coincidan sean rechazados, mientras que las opciones sin tipar sigan siendo utilizables.

Enforce generic types when passed to ReactFireOptions, update various types

Hey guys, will try to keep this short. Right now ReactFireOptions is generic on T but the type of initialData, which should be only of_ type T is of type T | any.

export interface ReactFireOptions<T = unknown> {
  idField?: string;
  initialData?: T | any;
  /**
   * @deprecated use initialData instead
   */
  startWithValue?: T | any;
  suspense?: boolean;
}

The result of this is that the generic parameter is useless, as we don't get any type enforcement on initialData. For example, this is fine:

interface MyInterface {
    thing: string;
}

const foo: ReactFireOptions<MyInterface> = {
    initialData: {
        thing: 2 // no complaints
    }
}

My suggestion is to change ReactFireOptions to this:

export interface ReactFireOptions<T = any> {
  idField?: string;
  initialData?: T;
  /**
   * @deprecated use initialData instead
   */
  startWithValue?: T;
  suspense?: boolean;
}

This still allows users to pass whatever they want to initialData when not supplying a generic type, but will cause Typescript to complain when using a generic type and the value passed to initialData does not match the provided type.

interface MyInterface {
    thing: string;
}

const foo: ReactFireOptions<MyInterface> = {
    initialData: {
        thing: 2 // complains, "Type 'number' is not assignable to type 'string'."
    }
}

Additionally, there are a few places using { [key: string]: unknown }, which can be expressed more clearly with Record<string, unknown>.

I have a branch with the following changes but I can't push it as I don't have permissions. Not sure if I need to ask for them somewhere.

Cheers! Great project, and I'm finding it very useful.