fix: load_all patch, and Roxygen update

[dsweber2]

This makes it so that quantile_reg and smooth_quantile_reg only get defined as new models if they aren't already in the current model namespace. Debugging these still requires restarting R; for everything else, there's devtools::load_all() (which works now).

In the process of writing this, roxygen ran into issues where the new version didn't recognize `%@%` and needed just a bare %@%.

[dajmcdon]

I think you should also delete .Rprofile. Once you make these minor changes, feel free to merge.