Make go() open non-local links in a new tab/window

 }
 
 export function go(url) {
-  if (url.startsWith("/http")) {
-    window.open(url.substring(1), "_blank")
+  if ((url.startsWith("http://") || url.startsWith("https://")) &&
+      !url.startsWith(window.location.origin)) {
+    window.open(url, "_blank")
   } else {
     history.replaceState({scroll: window.pageYOffset}, "title", window.location.href)
     updateArticle(url, 0)