Add support to chart not listed in documentation (sunburst, parallel categories)

[AlexisBRENON]

Hi,

I would like to contribute to this project, adding support for extra features, in particular parallel categories and sunburst.
However, I don't see them in the plotly-documentation/_posts folder.
Is it intended ? What is the better way to proceed (just update sub-module, add them manually, etc.)?

Kind.