https://paste.ee/p/ZzgpY (update: fixed things being highlighted inside strings) (update: claimed .PRG extension)
Download and save as an .xml file
In notepad++:
Language > Define your language ... > Import ...
Make sure you're using a light theme because custom highlighting settings don't support themes.
If it fails to import, try copying the text from the xml file into another file because notepad++ doesn't like that it was downloaded from the internet I guess.
Then Save as... and pick a different name because otherwise it won't show up in the list for some reason.
Only works with windows line endings because notepad++ is awful and broken.
