Hello,
I am the one who added all the Generation 8 and 9 Pokémon to the wiki. I looked over the raw data and it seems I placed an extra digit where the generation number goes, so it was designating Regieleki as Generation 80 instead of 8. I have fixed this now. It may take some time to reflect these changes, but it should take no longer than a few days.
If you ever spot any other errors, or other problems on the wiki, don't hesitate to create a new post or reach out to me directly.
Thank you for bringing it up and I hope you continue to bring up any wiki errors you come by. Take care.