Coming from (and asking for) NixOS/nixos-homepage#1865 (comment),

the https://github.com/matrix-org/matrix.to#url-scheme doc should probably specify what the correct https://matrix.to URL scheme to join a space (not a room) is?

Like how to write a https://matrix.to link which redirects e.g. to https://app.element.io/#/room/#space:nixos.org (if that's the UI), and equivalent for other clients?