prog8/syntax-files/Jetbrains-IDEs

Prog8 syntax highlighting file for the suite of Jetbrains IDEs
such as IntelliJ IDEA, Rider, and PyCharm.

Copy the file Prog8.xml to your IntelliJ/Rider/PyCharm filetypes folder.
If this folder doesn't yet exist, simply create it.
After installing this file, restart the IDE.

The exact location of that folder varies per operating system and
IDE version, but for me it is this one currently this on Linux:

  $HOME/.config/JetBrains/IntelliJIdea2024.3/filetypes/
  
For PyCharm on Mac OS, it is:

  $HOME/Library/Application Support/JetBrains/PyCharm2024.3/filetypes/

And on Windows it is:

  %USERPROFILE%\AppData\Roaming\JetBrains\PyCharm2024.3\filetypes\

etcetera.