SearchKit displays: be able to add description so end user knows the context

Currently on SearchKit displays we can set the name which ends up being used for the title and the URL. I've tried to add additional information there for end users so they understand the context of the results. E.g. "Only shows results for the current campaign". But that's awkward to stuff that all into the title. And also means one has to be careful that on the first save not to add those notes to the name so as to prevent an ungainly URL.

(The other option is to embed the SK into an afform, but that's a lot of extra work for just a bit of description.)

So a separate description field would be ideal.