Update generate.py

[OleBialas]

Hello.,

The docstring of generate_templates says:

    unit_params : dict[np.array] | dict[float] | dict[tuple] | None, default: None
        An optional dict containing parameters per units.
        Keys are parameter names:

            * "alpha": amplitude of the action potential in a.u. (default range: (6'000-9'000))

However, in default_unit_params_range (line 1649), alpha is defined differently

default_unit_params_range = dict(
    alpha=(100.0, 500.0),
    ...

I have updated the docstring to reflect this

Best,
Ole