federation-api: Note that create_join_event v2 should include heroes for nameless rooms
According to MSC3943
@@ -39,6 +39,15 @@ pub struct Request {
///
/// If `true`, membership events are omitted from `state` and redundant events are omitted from
/// `auth_chain` in the response.
+ ///
+ /// If the room to be joined has no `m.room.name` nor `m.room.canonical_alias` events in its
+ /// current state, the resident server should determine the room members who would be
+ /// included in the `m.heroes` property of the room summary as defined in the [Client-Server
+ /// `/sync` response]. The resident server should include these members' membership events in
+ /// the response `state` field, and include the auth chains for these membership events in
+ /// the response `auth_chain` field.
+ ///
+ /// [Client-Server `/sync` response]: https://spec.matrix.org/v1.5/client-server-api/#get_matrixclientv3sync
#[cfg(feature = "unstable-msc3706")]
#[ruma_api(query)]
#[serde(
