As per the discussion in https://github.com/ProjectMOSAIC/mosaic/issues/686, it might be nice to have a document doing a side-by-side comparison of `ggformula` and `ggplot2`. Uses: * demonstrate how much of `ggplot2` is available via `ggformula` * help migrate from `ggformula` to `ggplot2`, if desired * help people already familiar with `ggplot2` see how things can be done in `ggformula`.