how to get language auto complete on files that have exotic extensions

been playing around with [the templ html component system](https://templ.guide/)  on goland and there is a [plugin](https://plugins.jetbrains.com/plugin/23088-templ) that does syntax highlighting, but do you guys know how i can let Goland know that I should be able get auto complete for the html stuff and the go stuff as well?

i think maybe there's a list of filetypes that when recognized, are given this features and maybe i can just add the `.templ` file type on there?