Using time arrays in PinchedModel.get_initial_spectra

[Sheshuk]

Closes #221

[github-actions[bot]]

Result of Benchmark Tests

Benchmark	Min	Max	Mean
python/snewpy/test/test_snowglobes.py::test_simulation_chain_benchmark	4.63	4.78	4.73 +- 0.06

[JostMigenda]

Minor note: If t can now also be an array, the type of t in the docstring should be updated accordingly.

[Sheshuk]

Minor note: If t can now also be an array, the type of t in the docstring should be updated accordingly.

astropy.Quantity is an extension of ndarray, so we're actually using them, not ndarray of astropy.Quantity, for example

>>> T = np.linspace(0,10) << u.s
>>> type(T)
astropy.units.quantity.Quantity

so the current docstring is (now even more) correct

[Sheshuk]

Thanks! Yes these variadic generics look like they would make the signatures much cleaner. In general I think it would be good to add the type hints throughout snewpy, but that's a separate task.