fix name.

db/moonstreamdb/models.py

@@ -239,8 +239,8 @@ class PolygonLabel(Base):  # type: ignore
     # Undescribed indexes
     """
     Migration: alembic\versions\5f5b8f19570f_added_index_for_address_type_and_name_.py
-    
-    Index: "polygon_labels_address_type_and_name_idx" created manually.
+
+    Index: "ix_polygon_labels_address_label_label_data_type_and_name" created manually.
     By fields: (address, label, (label_data->>'type'), (label_data->>'name'))
     Reason: https://github.com/sqlalchemy/alembic/issues/469#issuecomment-441887478
     """