Message edits lost after restarts

[TobiasFella]

Happens both in NeoChat and Quaternion.

When a message is edited (no matter by whom and in which client), the edit shows up fine in libQuotient based clients if it comes in live (as new messages, not historical messages). after restarting the client, the message shows up in the unedited form.

AFAICT the replacement is only processed in Room::Private::addNewMessageEvents but not in Room::Private::addHistoricalMessageEvents, which would explain this.