These light wrappers around bbr::build_path_from_model() enable quickly
jumping to a model file in RStudio or any other editor supported by
utils::file.edit().
open_stanmod_file(.mod)
open_standata_file(.mod)
open_staninit_file(.mod)
open_stan_fitted_params_file(.mod)open_stanmod_file(): Open <run>.stan.
open_standata_file(): Open <run>-standata.R.
open_staninit_file(): Open <run>-init.R (not relevant for standalone
generated quantities).
open_stan_fitted_params_file(): Open <run>-fitted-params.R (only relevant for
standalone generated quantities).