Recognise castling represented in UCI as e.g. e1h1 instead of e1g1

[UnkindPartition]

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Hi Mario, thank you for this nice library. I've gotten some good use out of it.

This small PR fixes an issue I ran into when interacting with Lichess API — it represents castling Chess960-style, as e1h1 instead of e1g1. So I've added a bit of code to recognise that notation as well.