Add link to gallery of R charts to show what's possible

[cjrace]

Is your feature request related to a problem? Please describe.
Spotted this and thought it might be helpful to share more widely for inspiration

Describe the solution you'd like
A link to https://r-graph-gallery.com/ with some context around it, likely on the R page

Describe alternatives you've considered
Not thought much more about it yet

Additional context
Nothing else to add