Use "# %%" instead of "#%%" as default cell delimiter (or allow customization)

By default the extension inserts #%% after executing the last cell in a file. This is also the documented cell delimiter. But it’s not compliant with flake8 and other popular python linters, which expect at least one whitespace after the #. In general, it’s not possible to configure these linters to ignore a specific pattern, but just to disable predefined rules. I understand that exploratory work often violates conventions and produces “write-only” code. But I believe that changing the default delimiter to # %% is a simple change that will keep flake8 from flooding the problems view. You could maybe offer the option to change this default delimiter, given that you already offer the option to change the delimiter regex (which by default is also compatible with # %%)…

[memeplex]

We’ll check telemetry first though to see how many people have changed the regex.

For all the hate that telemetry gets, it’s great that you can do that kind of “data-driven development”.

[IanMatthewHuff]

Validated.