Remove aliases field from /publicRooms

[richvdh]

... or at least make a suggestion that servers don't return it

Link to problem area:

https://spec.matrix.org/unstable/client-server-api/#get_matrixclientr0publicrooms

Issue

The spec for /publicRooms suggests that servers should return an aliases field from the /publicRooms. However, MSC2432 changed most of the rest of the spec so that m.room.aliases events are no longer treated specially, and matrix-org/synapse#6970 removed support for this field from Synapse.

Although this endpoint was never called out explicitly in MSC2432, I think that was just an oversight. It might be nice if the situation was at least made clearer in the spec.

Expected behaviour

Remove the field altogether? Or call out that it may not be returned by common server impls, and recommend that servers don't populate it?

[turt2live]

ah ha, we do have an issue for this. In a different line of investigation we ran across this exact issue. Proposed for removal here: #3624