Add the select_pronoun method to UserPreferencesV0 & impl Default for UserPreferences

Signed-off-by: Ben Aaron Goldberg <ben@benaaron.dev>

src/user_preferences/mod.rs

@@ -29,6 +29,12 @@ pub enum UserPreferences {
 	V0(v0::UserPreferencesV0)
 }
 
+impl Default for UserPreferences {
+	fn default() -> Self {
+	    UserPreferences::V0(UserPreferencesV0::default())
+	}
+}
+
 /// Functionality provided by any version of user preferences
 ///
 /// See also: [`UserPreferences`]
@@ -76,6 +82,14 @@ pub trait Preference {
 	fn into_prefstring(&self) -> String {
 		BASE32_NOPAD.encode(&self.into_prefstring_bytes())
 	}
+
+	fn select_pronoun<'a>(&self, settings: &'a InstanceSettings, name: Option<&str>) -> Result<&'a Pronoun, ParseError> {
+		let seed = match name {
+			Some(name) => name.as_bytes(),
+			None => &[],
+		};
+		Ok(self.into_weighted_table(settings)?.select_today(seed))
+	}
 }
 
 impl Preference for UserPreferences {