Fix gtk tags output

src/main.rs

@@ -135,7 +135,9 @@ impl Serialize for Env {
             name_id_map.reserve(self.output_names.len());
             let mut id = 0;
             for (_, value) in &self.output_names {
+                if !name_id_map.contains_key(value.as_str()) {
                     name_id_map.insert(value, id);
+                }
                 id += 1;
             }
             state.serialize_field("gtk_ids", &name_id_map)?;