matrix-js-sdk

7ea820f6 - Add `Event.relationsCreated` event to listen for future relations collections

Add `Event.relationsCreated` event to listen for future relations collections If you ask for relations but none currently exist, we return `null` to avoid the overhead of many empty relations objects in memory. However, we still want some way to alert consumers when one _is_ later made, so this event level event provides that. Part of https://github.com/vector-im/riot-web/issues/9572 Part of https://github.com/vector-im/riot-web/issues/9485