Fix rsx autocomplete and diagnostics in the root; provide better completions after attributes are finished (#2656)

* fix rsx autocomplete and diagnostics in the root; provide better completions after attributes are finished

* clean up pr to use internal child parsing

* Fix peek_lowercase name

* fix comma diagnostics in the root

* Fix parsing components with a path

* remove simple routes trailing comma

* Fix incomplete_root_elements test

* Remove trailing commas from root body node in tests

---------

Co-authored-by: Jonathan Kelley <jkelleyrtp@gmail.com>

packages/router/examples/simple_routes.rs

@@ -92,7 +92,7 @@ fn Route1(user_id: usize, dynamic: usize, query: String) -> Element {
 fn Route2(user_id: usize) -> Element {
     rsx! {
         pre { "Route2{{\n\tuser_id:{user_id}\n}}" }
-        {(0..user_id).map(|i| rsx!{ p { "{i}" } })},
+        {(0..user_id).map(|i| rsx!{ p { "{i}" } })}
         p { "Footer" }
         Link {
             to: Route::Route3 {