PlotlyJS doesn't work without ORCA installed

The "Saving figures" section in the index page of the documentation says that

> "If you would like to save your figures to files in a format other than json and html, you will need to install the ORCA.jl pacakge."

I was getting an error that ORCA isn't installed by trying to run `using PlotlyJS`. Until I installed ORCA, I wasn't able to use PlotlyJS. According to the documentation, it seems to imply that you only need ORCA.jl if you plan on saving figures.