fix: typo in the scootaloo_mentions var

src/lib.rs

@@ -50,7 +50,7 @@ pub async fn run(config: Config) {
             (
                 format!("@{}", s.twitter_screen_name),
                 format!(
-                    "{}@{}",
+                    "@{}@{}",
                     s.mastodon_screen_name.as_ref().unwrap(),
                     s.base.split('/').last().unwrap()
                 ),