Refactor routing in App component to enhance navigation and improve error handling by integrating dynamic routes and updating the NotFound route.

node_modules/micromark-extension-gfm-footnote/index.js

@@ -0,0 +1,3 @@
+// Note: types are exported from `dev/index.d.ts`.
+export { gfmFootnote } from './lib/syntax.js';
+export { gfmFootnoteHtml, defaultBackLabel } from './lib/html.js';