Fix small mistakes in sil example

[Impelon]

Seems like there are a few small mistakes in the sil example.
Consider doing a sqash-merge of these small commits :)

[Impelon]

The test to see if examples/sil_example.ipynb runs is currently not included in the Build workflow. Probably because it would take 24 * 3600 seconds to run it.

If one applies these fixes and reduces the time given for the simulation, the test works fine though. One could consider replacing the until parameter in examples/sil_example.ipynb during the execution of the workflow with sed or similar...
Might be a bit overkill though, especially because using sed will only work as long as the example does not significantly change.

[marvin-steinke]

Ah yes the SiL example is kind of a WIP right now. Thanks for the fixes :)

[birnbaum]

thanks a lot!