Month and WeekDay translations

[FrederickFrance]

Hi,

When I created my PR, I was thinking "Oh, I could add translations for months and weekday". But I don't know the correct best practices for this kind of features.

Should I use https://crates.io/crates/lingua and a match like this example ?

fn hello(language: Option<Language>) -> &'static str {
    match language {
        Some(Language::French) => "Bonjour",
        _ => "Hello",
    }
}