use %sapper.scripts%

test/app/templates/2xx.html

@@ -32,6 +32,6 @@
 	<!-- Sapper creates a <script> tag containing `templates/main.js`
 	     and anything else it needs to hydrate the app and
 	     initialise the router -->
-	<script src='%sapper.main%'></script>
+	%sapper.scripts%
 </body>
 </html>