include ban reasons when banning a user that already had a member event

The case where the user never had a member event in the room is already
handled correctly.

book/changelog.md

@@ -242,6 +242,9 @@ This will be the first release of Grapevine since it was forked from Conduit
     ([!158](https://gitlab.computer.surgery/matrix/grapevine/-/merge_requests/158))
 28. Fix read receipts not being sent over federation (or only arbitrarily late)
     ([!162](https://gitlab.computer.surgery/matrix/grapevine/-/merge_requests/162))
+29. Fix bug where ban reasons would be ignored when the banned user already had
+    a member event in the room.
+    ([!185](https://gitlab.computer.surgery/matrix/grapevine/-/merge_requests/185))
 
 ### Added
 

src/api/client_server/membership.rs

@@ -288,6 +288,7 @@ pub(crate) async fn ban_user_route(
                         RoomMemberEventContent {
                             membership: MembershipState::Ban,
                             join_authorized_via_users_server: None,
+                            reason: body.reason.clone(),
                             ..event
                         }
                     })