Add plotInset parameter to style

[AndreiKingsley]

https://nbviewer.org/github/JetBrains/lets-plot-kotlin/blob/master/docs/examples/jupyter-notebooks/f-4.7.1/theme_plot_inset.ipynb

[lucas-watkins]

Hello, if this issue is still available may I please try to solve it?

[AndreiKingsley]

Yes, you are welcome.

You need to add the inset property to the PlotCanvas custom style configuration. First you need to research its behavior in Lets-Plot and design API for it.

[lucas-watkins]

I have implemented an API that is very similar to the existing one that handles margins. However, I read in CONTRIBUTING.md that all new APIs must come with documentation. Is it appropriate to add documentation in the docs folder or the examples folder in this case?

[AndreiKingsley]

Custom style API is still unstable, we haven't done documentation and tests yet, so you can add it without them for now.