You should add the Linux icon next to the windows icon for the PC version, and include Linux as a supported OS. Renpy already generated the .sh file which is for Linux. Otherwise Linux users might not consider checking out your VN thinking it wasn't supported. You might also need to update your manifest file for the itch.io page so the itchio app will recognize the linux file. I can assure you, the VN runs fine in Linux since that's my OS of choice.