Optional examples section in JOSS papers

[hodgestar]

While reviewing the qiskit-dynamics section I thought it might be nice to allow submission to include an examples section within the JOSS paper itself, either as a section near the end or as an appendix.

The advantages of this over examples within the project documentation are:

• Readers can see the examples straight away without having to navigate through to the project documentation.
• The examples in the paper can be tailored to JOSS readership (i.e. often industry professionals working in the field) whereas examples in the project documentation often cater to a wider audience.
• The examples in the paper stay accessible even if the project documentation changes or becomes defunct, so it would allow the JOSS papers to be more useful to readers many decades from now.

Adding examples might made rendering the paper a bit more complex in that authors will want to include code snippets, plots, etc. I don't know which such things are already supported.