Update CONTRIBUTING.md with prettier information

CONTRIBUTING.md

@@ -8,6 +8,8 @@ We welcome your pull requests (PRs).
 For minor fixes (e.g., documentation improvements), feel free to submit a PR directly.
 If you would like to implement a new feature or a bug, please make sure you (or someone else) has opened an appropriate issue first; in your PR, please mention the issue it addresses.
 
+Note that since #2048 al-folio uses the [prettier formatter](https://prettier.io/) for its code, meaning all new submitted code must conform to its standard. If you don't have prettier installed for your setup and the `prettier` code check fails when submitting a PR, you can check the referred failed action in our repo. In that action there will be an artifact with an HTML diff showing the needed changes.
+
 ## Issues
 
 We use GitHub issues to track bugs and feature requests.