Simulation documentation does not explain **kwargs

[arunpersaud]

On https://picmi.readthedocs.io/en/latest/standard/simulation.html it is unclear what the possibilities for **kw are. There should be a link to the baseclass which should explain the options.

[dpgrote]

Thanks, good point. The kw options would be the code specific options, for example warpx_evolve_scheme for WarpX.