docs(demo): Use Router import

examples/concurrent/src/routing/index.tsx

@@ -1,12 +1,12 @@
-import { RouteController } from '@anansi/router';
+import { Router } from '@anansi/router';
 import type { History } from 'history';
 
 import NotFound from '@/components/NotFound';
 
 import { routes, namedPaths } from './routes';
 
 export function createRouter(history: History) {
-  return new RouteController({
+  return new Router({
     history,
     namedPaths,
     routes,