Feature request: PRONOUNS

[amyipdev]

Per RFC 9554, PRONOUNS is a supported field for vCards. Support is not currently included in the vCard library; at the moment, I have to use an unchecked X-Property, which requires an unsafe block:

vc.x_properties = Some(vcard::Set::from_hash_set({
    let mut xp = std::collections::HashSet::new();
    let pronouns = {
        let mut pronoun = XProperty::from_text(
            unsafe {vcard::XPropertyName::from_string_unchecked("PRONOUNS".to_string())},
            vcard::values::text::Text::from_str(&member.pronouns)?,
        );
        pronoun.language = Some(en.clone());
        pronoun
    };
    xp.insert(pronouns);
    xp
})?);

Please add this as a stable feature!