Function fluent_locale::negotiate::filter_matches

pub fn filter_matches<'a, R: 'a + Into<LanguageIdentifier> + Clone, A: 'a + Into<LanguageIdentifier> + Clone>(
    requested: impl IntoIterator<Item = &'a R>, 
    available: impl IntoIterator<Item = &'a A>, 
    strategy: NegotiationStrategy
) -> Vec<&'a A>