Designspaces: handle localization

[madig]

The spec describes e.g. https://fonttools.readthedocs.io/en/latest/designspaceLib/xml.html#stylename-familyname-stylemapstylename-stylemapfamilyname-elements-localised-names-for-instances to assign localized names. Norad may want to handle that.

[cmyr]

Yes we will definitely want to handle this, and I can't really imagine doing it without custom serde impls. I wish that the spec were a bit clearer on expectations here; in particular, is it possible to have only localized names, or should there only be localized names if there is also a default name?

My first thought is to replace the use of Option<String> for this type with an Option<LocalizedString> that is some custom type that wraps some sort of collection..

[madig]

My understanding last time is that the normal attribute for e.g. family name is lang "en", unless there's an explicit "en" entry in localized family name, but I haven't thought about it too hard. designspaceLib uses a dict[str, str] for these localized attributes.