Support Nested Routing and Manifests

[ryansolid]

Solid App Router supports nested routing. They do so by naming a file the same name as the folder. In so it acts as the parent. I haven't added that yet.

In addition we need to make sure that manifest lookup for preload works as well.

[jceb]

To improve the status quo, this line https://github.com/solidjs/solid-start/blob/main/packages/start/components/Outlet.tsx#L22 could be extended to let temp = list.find(o => o._id !== '/' && o._id && id.startsWith(o._id));. This would make it possible to support this kind of file structure:

/account/registration.jsx
/account/registration/index.jsx
/account/registration/otherpage.jsx

That generates this route structure:

      <Routes>
        <Route path="/account/registration" element=..>
          <Route path="/" element=.. >
            <Route path="/" />
            <Route path="/otherpage" element=.. />
          </Route>
        </Route>
      </Routes>

Compared to the previous route structure that doesn't work at all:

      <Routes>
        <Route path="/account/registration" element=..>
          <Route path="/" element=.. >
            <Route path="/">
              <Route path="/otherpage" element=.. />
            </Route>
          </Route>
        </Route>
      </Routes>

[ryansolid]

I think the route structure should be ideally:

<Routes>
  <Route path="/account/registration" element=..>
    <Route path="/" element=.. />
    <Route path="/otherpage" element=.. />
  </Route>
</Routes>

There is no need for an intermediate slash path.. technically in this example only the top route is the shared layout.

[jceb]

Oh yes, you're right. The patch produces exactly that route

[jceb]

Could you take a look at it and merge it to main/release it?