Fix incorrect state of leave->leave

As mentioned in PR review, it is possible for moderators in a room to race at kicking someone, resulting in multiple leave events.

event-schemas/schema/m.room.member

@@ -40,7 +40,7 @@ description: |-
     "","to ``invite``","to ``join``","to ``leave``","to ``ban``","to ``knock``"
     "from ``invite``","No change.","User joined the room.","If the ``state_key`` is the same as the ``sender``, the user rejected the invite. Otherwise, the ``state_key`` user had their invite revoked.","User was banned.","Not implemented."
     "from ``join``","Must never happen.","``displayname`` or ``avatar_url`` changed.","If the ``state_key`` is the same as the ``sender``, the user left. Otherwise, the ``state_key`` user was kicked.","User was kicked and banned.","Not implemented."
-    "from ``leave``","New invitation sent.","User joined.","Must never happen.","User was banned.","Not implemented."
+    "from ``leave``","New invitation sent.","User joined.","No change.","User was banned.","Not implemented."
     "from ``ban``","Must never happen.","Must never happen.","User was unbanned.","No change.","Not implemented."
     "from ``knock``","Not implemented.","Not implemented.","Not implemented.","Not implemented.","Not implemented."