Hexmap: Week 0x12

A small tale of the joy in being an integrated product manager, designer, and developer: I decided to make theming (e.g. dark mode) into a user preference, which required implementing select lists in forms, and found that the performance-prioritizing nature of Rust means that preserving order of hash maps (dictionaries) is DIY. So I spent 15 minutes settling on the indexmap crate, enabled the preserve_order feature on Minijinja, and now the list of themes is in the order I intended.