MSC3773: Notifications for threads (#3773)
* Add initial MSC for notfications for threads.
* No longer depends on MSC3664.
* Fix events in diagram.
* Major simplification.
* Add missing words.
* Add a note about reactions.
* Clarify homeserver behavior when processing push rules.
* Link to a spec version instead of latest.
Co-authored-by: Travis Ralston <travisr@matrix.org>
* Update 3773-notifications-for-threads.md
typoe
* Clarify wording.
* Update how homeservers are to partition threads.
Co-authored-by: Travis Ralston <travisr@matrix.org>
Co-authored-by: Matthew Hodgson <matthew@matrix.org>
