[Feature Request] Allow option to remove/omit fragment prefix naming for better re-use

I'm seeing the benefits of not prefixing generated fragments with the parent's name.

Current:
```javascript
export interface RestaurantFragment {
__typename: "Restaurant";
menus: MenuFragment_restaurant | null;
}

export interface MenuFragment_restaurant {
__typename: "Menu";
name: string;
}
```

Proposed:
```javascript
export interface RestaurantFragment {
__typename: "Restaurant";
menus: MenuFragment_restaurant | null;
}

export interface MenuFragment {
__typename: "Menu";
name: string;
}
```

In the second case, the `MenuFragment` will be the same at all levels in the GraphQL data tree, whereas the current method will prefix the fragment with the parent fields name, making re-use much more difficult.

No source file, test, or entry point is named. Start by locating the TypeScript GraphQL fragment-name generation path and its option handling, then add coverage showing that nested fragments can omit the parent-name prefix and produce the proposed reusable names.

Written by the indexing model from the issue text.