Fix params type when the route name is an union

[zoontek]

Let's suppose you have this router:

export const Router = createRouter({
  Home: "/",
  ProjectRoot: "/projects/:projectId",

  DevelopersApi:
    "/projects/:projectId/:projectEnv{live|sandbox}/developers/api",
});

const doSomething = (name: "ProjectRoot" | "DevelopersApi") => {
  Router.push(name, { projectId: "" }); // no error before, now there's one
};

Before, there was no error. The route name could be either ProjectRoot or DevelopersApi, but the params was not an intersection or both those route params.