`<relation>` in formats is badly visualised on both ends

[bansp]

The fact that the target is badly visualised if the spec is absent is already mentioned in another issue (#410).

But I have only now realised that also the source is umph. This is probably because the relationship part was transplanted from the Watchtower section without adjusting for the source (it had been used to show relationships among standards, rather than between formats and standards).

This issue should probably get prioritised some time soon.