style(core): remove type hints

Signed-off-by: David Wallace <david.wallace@tu-darmstadt.de>

Author: MyPyDavid

rdmo/core/pandoc.py

@@ -4,7 +4,6 @@
 import re
 from pathlib import Path
 from tempfile import NamedTemporaryFile
-from typing import Optional
 
 from django.apps import apps
 from django.conf import settings
@@ -103,7 +102,7 @@ def get_pandoc_args(export_format, context):
     return pandoc_args
 
 
-def get_pandoc_reference_document(export_format, context) -> Optional[Path]:
+def get_pandoc_reference_document(export_format, context):
     # collect all configured reference documents
     reference_documents = get_pandoc_reference_documents(export_format, context)