ArtBot is just an interface to the AI Horde's image generation service. In order to add features like this to ArtBot, they need to first be added to Horde. You can request this at Haidra-Org/AI-Horde.
Aright, i thought Adetailer was an extension more on the users end since there was already options like "GFPGAN". But i'm guessing now, "GFPGAN" is there because AI Horde already supports a few "Post-processing" options like that to use
Add the webui extension Adetailer to artbot