add rewritten router book and fix features code

docs/router/src/example/full-code.md

@@ -0,0 +1,9 @@
+# Full Code
+
+```rust,no_run
+# // Hidden lines (like this one) make the documentation tests work.
+# extern crate dioxus;
+# extern crate dioxus_router;
+# extern crate dioxus_web;
+{{#include example.rs}}
+```