fix more annotations

Author: AbstractUmbra

mystbin/backend/utils/db.py

@@ -16,6 +16,8 @@
 You should have received a copy of the GNU General Public License
 along with MystBin.  If not, see <https://www.gnu.org/licenses/>.
 """
+from __future__ import annotations
+
 import asyncio
 import datetime
 import difflib