Ladybird+LibWeb: Use old error.html template for navigation errors again

Author: https://github.com/bplaat
Commit: 04ee15a5ad
Pull-request: https://github.com/SerenityOS/serenity/pull/21176
Reviewed-by: https://github.com/ADKaster ✅

Userland/Libraries/LibWeb/Loader/GeneratedPagesLoader.h

@@ -6,16 +6,20 @@
 
 #pragma once
 
-#include <LibWeb/Loader/Resource.h>
 #include <LibWeb/Fetch/Infrastructure/HTTP/Responses.h>
+#include <LibWeb/Loader/Resource.h>
 
 namespace Web {
 
 String resource_directory_url();
 void set_resource_directory_url(String);
+String error_page_url();
+void set_error_page_url(String);
 String directory_page_url();
 void set_directory_page_url(String);
 
+ErrorOr<String> load_error_page(AK::URL const&);
+
 ErrorOr<String> load_file_directory_page(LoadRequest const&);
 
 }