New Features
- add enable/disable cell number in .py files ([1428](https://github.com/fastai/nbdev/pull/1428)), thanks to [dienhoa](https://github.com/dienhoa)
- When exporting a notebook to a .py file, we currently have something like ` %% {nb_path} {cell_number}` at the beginning of each exported cell.
- This PR adds one new setting in the setting.ini: `cell_number`. When set to False, we disable the `cell_number` discussed above.
- Side effect: The `cell_number` is used to update the changes from .py back to the notebook, so disabling it also disables this feature.
Bugs Squashed
- showdoc: SyntaxWarning: invalid escape sequence with Python 3.12 ([1396](https://github.com/fastai/nbdev/issues/1396))