add example of writing a Stan program for use with LOO and link to this vignette: https://mc-stan.org/loo/articles/loo2-with-rstan.html and corresponding ArviZ docs https://arviz-devs.github.io/EABM/Chapters/Prior_posterior_predictive_checks.html to section https://mc-stan.org/docs/stan-users-guide/cross-validation.html#approximate-cross-validation
add example of writing a Stan program for use with LOO and link to this vignette: https://mc-stan.org/loo/articles/loo2-with-rstan.html
and corresponding ArviZ docs https://arviz-devs.github.io/EABM/Chapters/Prior_posterior_predictive_checks.html
to section https://mc-stan.org/docs/stan-users-guide/cross-validation.html#approximate-cross-validation