message: web: fix slash-less source route
diff: @@ -71,7 +71,7 @@ pub(super) fn build_routes() -> Routes {
  super::builds::build_list_handler,
  );
  routes.internal_page(
  - "/crate/:name/:version/source",
  + "/crate/:name/:version/source/",
  super::source::source_browser_handler,
  );
  routes.internal_page(
  