Update api-routes.mdx for new @solidjs/start package (#990)

Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>

src/routes/solid-start/building-your-application/api-routes.mdx

@@ -201,7 +201,7 @@ export const client = createTRPCProxyClient<AppRouter>({
 Finally, you can use the `fetch` adapter to write an API route that acts as the tRPC server.
 
 ```tsx title="routes/api/trpc/[trpc].ts"
-import { type APIEvent } from "solid-start/api";
+import { type APIEvent } from "@solidjs/start/server";
 import { fetchRequestHandler } from "@trpc/server/adapters/fetch";
 import { appRouter } from "~/lib/router";