invalid characters in notebook name #96
Description
when creating a new notebook, the name isn't checked for invalid characters for filenames. So I was a able to create a notebook with the name dart/flutter that leads to faulty behaviour
a notebook with that name was actually visible. When opening it, it wasn't properly opened, the whole app was in a faulty state. After restarting, the app was back to normal, the notebook was gone and I can't see any file dart/flutter.md (invalid on linux) or a folder dart in the .noteorganiser folder