Handle Telegram/* edits on Matrix

[Mikaela]

Is your feature request related to a problem? Please describe.

When a message is sent from Telegram to Matrix and edited, it appears at Matrix with the (edited) suffix rather than the original message getting edited.

Describe the solution you'd like

I would like Matterbridge to edit the message it has relayed, I think the specification is somewhere in https://matrix.org/docs/spec/client_server/r0.6.0

Describe alternatives you've considered

I don't see other alternatives than the current behaviour and this request.

Additional context
-

[MayeulC]

Matrix has support for this, but it currently sits in matrix-org/matrix-spec-proposals#1849 which isn't yet part of the spec. There is one notable difference with the current (temporary) implementation, in that m.relationship is currently m.relates_to. Otherwise, the implementation is as-described. Not sure if best to implement now or once the MSC is merged?

Edit: one comment on that MSC said that clients could send both events during the transition period.

[Mikaela]

I think it may be better to wait

[Sorunome]

The MSC seems mostly stale currently? with little activity.

Clients do, however, already implement editing with m.relates_to. If that MSC goes through with m.relationship a change would be trivial to adapt it, though it is probably more likely that the MSC changes to m.relates_to.

[42wim]

Fixed with #1286