events: Make IgnoredUserListEventContent non-exhaustive

ruma-events/src/ignored_user_list.rs

@@ -11,6 +11,7 @@ pub type IgnoredUserListEvent = BasicEvent<IgnoredUserListEventContent>;
 
 /// The payload for `IgnoredUserListEvent`.
 #[derive(Clone, Debug, Deserialize, Serialize, BasicEventContent)]
+#[cfg_attr(not(feature = "unstable-exhaustive-types"), non_exhaustive)]
 #[ruma_event(type = "m.ignored_user_list")]
 pub struct IgnoredUserListEventContent {
     /// A list of users to ignore.
@@ -18,6 +19,13 @@ pub struct IgnoredUserListEventContent {
     pub ignored_users: Vec<UserId>,
 }
 
+impl IgnoredUserListEventContent {
+    /// Creates a new `IgnoredUserListEventContent` from the given user IDs.
+    pub fn new(ignored_users: Vec<UserId>) -> Self {
+        Self { ignored_users }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use matches::assert_matches;