Netflix has adapted plenty of video games into series and films, from “Castlevania” to “Dota: Dragon’s Blood.” Even “Pokémon Go’s” lesser-known predecessor, “Ingress,” was transposed into an animated series. And one of the more convincing successes, “The Witcher,” headlined by Henry Cavill of “Man of Steel” fame, has a second season coming in December and is already renewed for a third.