How do I use gjs highlighting?

[NullVoxPopuli]

I got an error:

Error occurred:

- While rendering:
  -top-level
    application
      post
        markdown-to-html


Uncaught (in promise) Error: Assertion Failed: Language "gjs" not found. Have you configured Prism correctly?

There was an error running your app in fastboot. More info about the error: 
 Error: Assertion Failed: Language "gjs" not found. Have you configured Prism correctly?
    at assert (/tmp/broccoli-168736dwVHBvJY1q1J/out-531-broccoli_merge_trees/assets/@ember/debug/index.js:145:1)
    at /tmp/broccoli-168736dwVHBvJY1q1J/out-531-broccoli_merge_trees/assets/addon-tree-output/ember-showdown-prism/initializers/showdown-extension.js:86:1
    at String.replace (<anonymous>)
    at /tmp/broccoli-168736dwVHBvJY1q1J/out-531-broccoli_merge_trees/assets/addon-tree-output/ember-showdown-prism/initializers/showdown-extension.js:59:1
    at showdown.Converter.makeHtml (webpack://__ember_auto_import__/./node_modules/.pnpm/showdown@2.1.0/node_modules/showdown/dist/showdown.js?:299:167)

maybe I could opt out of prism? prism is unmaintained.

highlight.js or shiki are maintained