add: link prepend

prepends/link.typ

@@ -0,0 +1,15 @@
+// Adds an "internal" class to links that stay within the application,
+// allowing them to be styled differently from external links.
+#show link: it => {
+  let dest = it.dest
+  if type(dest) == str {
+    let is-internal = dest.starts-with("/") or dest.starts-with(".")
+    let attrs = (href: dest)
+    if is-internal {
+      attrs = (href: dest, class: "internal")
+    }
+    html.elem("a", attrs: attrs, it.body)
+  } else {
+    it
+  }
+}