I don't claim to know how it works, but it shouldn't be too difficult. If it's simple they could just add those pronouns as extra options that could fill in places where <gender> is mentioned in dialogue, then create a selection for it somewhere. That said I'm sure the more conservative parts of the community would be upset, as shown by the brilliant first comment in this thread and all the people that liked it (because apparently they don't have anything better to do with themselves than laugh at strangers on the internet). I wouldn't get your hopes up about it, but you never know.