Allows the Settings > Hotkeys screen to be localised, including hotkey decriptions, groups and contexts.
The hotkey names are exposed to localisation via KeycodeExts. Hotkey modifiers are similarly exposed via ModifersExts.
The Settings > Input screen has a Zoom Modifier dropdown, which shows the localised modifier name.
The --check-yaml utility command is taught to recognise all hotkey translation, so it can validate their usage.
Any struct which overrides object.Equals(object obj) should implement IEquatable<T> to gain a more efficient Equals(T other) overload. This overload will be used by hashing collections like Dictionary which enables them to check equality without boxing the struct.
