Add note about using PUT /state/m.room.member/
@@ -19,11 +19,15 @@ POST /_matrix/client/r0/rooms/{roomId}/ban
POST /_matrix/client/r0/rooms/{roomId}/unban
POST /_matrix/client/r0/rooms/{roomId}/join
POST /_matrix/client/r0/join/{roomIdOrAlias}
+PUT /_matrix/client/r0/rooms/{roomId}/state/m.room.member/{userID}
```
If specified the `reason` field will be added to the generated membership
event's content.
+*Note: `/state/m.room.member` API currently allows this as clients can specify
+arbitrary content already*
+
Clients may choose to display the reason for membership events in a room,
though may not do so if e.g. they have collapsed a set of membership changes.
