All the languages supported are in the init.example.el file seen here: https://github.com/hlissner/doom-emacs/blob/develop/init.exa...
Uncomment them, run doom refresh. Check their module under https://github.com/hlissner/doom-emacs/tree/develop/modules/... for any external requirements that they need or flags that they support.
;;hy ; readability of scheme w/ speed of python
;;rust ; Fe2O3.unwrap().unwrap().unwrap().unwrap()
;;javascript ; all(hope(abandon(ye(who(enter(here))))))
;;hy ; readability of scheme w/ speed of python
;;rust ; Fe2O3.unwrap().unwrap().unwrap().unwrap()
;;javascript ; all(hope(abandon(ye(who(enter(here))))))