fix trailing whitespace in main.rs

src/main.rs

@@ -56,7 +56,7 @@ async fn create(state: &State<Mutex<GlobalState>>, url: &str, secret: Option<&st
     if actual_len < 1 || actual_len > 64 {
         return (Status::BadRequest, "invalid length".to_owned());
     }
-    
+
     loop {
         let link_id = if !custom_link {
             linkgen::generate_link_id(actual_len)