Add SolidStart support

[thomasbuilds]

Would be great to officially support SolidStart.

Shouldn't be much work since it already works like this:

// src/app.tsx
import { Suspense } from "solid-js";
import { Router } from "@solidjs/router";
import { FileRoutes } from "@solidjs/start/router";
import { inject } from "@vercel/analytics";
import "./app.css";

export default function App() {
  return (
    <Router
      root={(props) => (
        <Suspense>
          {props.children}
        </Suspense>
      )}
    >
      <FileRoutes />
    </Router>
  );
}

inject();