feat(DocLink): support absolute urls

Author: std-microblock

src/lib/doc-index.ts

@@ -57,6 +57,12 @@ async function getOrBuildKeyIndex(): Promise<Map<string, string>> {
  */
 export async function getLinkToKey(key: string): Promise<string | undefined> {
   const index = await getOrBuildKeyIndex();
+  if (key.startsWith("/")) {
+    if (Object.values(index).some(slug => `/${slug}/` === key || `/${slug}` === key))
+      return key;
+    else
+      return undefined;
+  }
   const slug = index.get(key);
   if (!slug) return undefined;
   return `/${slug}/`;