removeAutoFieldEnhancement method
- {required AnkiMapping mapping,
 - required Field field}
 
Removes a given mapping's persisted auto enhancement for a given
field.
Implementation
void removeAutoFieldEnhancement({
  required AnkiMapping mapping,
  required Field field,
}) async {
  /// -1 is reserved for the auto enhancement.
  mapping.enhancements![field.uniqueKey]!
      .remove(AnkiMapping.autoModeSlotNumber);
  _database.writeTxnSync(() {
    _database.ankiMappings.putSync(mapping);
  });
}