Use format specifiers instead of percent format

src/marshmallow/fields.py

@@ -628,7 +628,7 @@ def schema(self):
         return self._schema
 
     def _nested_normalized_option(self, option_name: str) -> list[str]:
-        nested_field = "%s." % self.name
+        nested_field = f"{self.name}."
         return [
             field.split(nested_field, 1)[1]
             for field in getattr(self.root, option_name, set())