MSC 2312: Matrix URI scheme proposal matrix-org/matrix-spec-proposals#2312 is nearing completion.

Describe the solution you'd like
More clients are going to implement that scheme, it would be nice to generate a clickable matrix: link, or automatically redirect to one like some services are doing (zoom, microsoft teams).

It would be nice not to put the user in a loop due to #191, so not automatically activate it, and de-emphasize that option when the user already comes from a matrix: scheme.

Additional context
Nheko and Quaternion are the only clients I have listed on matrix.to besides Element. Ironically, they both implement the new scheme (though at least on Linux, they do not register as protocol handlers).