Change `search-update` to be consistent with new search.

[cholmes]

I just realized the search-update should also be updated for consistency. Elsewhere (#887) I mentioned planet data stats could also use an update. I think that one is 'nice to have', but probably not essential. But search-update seems like it really should have the same behavior. I'm only trying it out now - I had thought it might just take JSON instead of having arguments, but just realized it has the arguments, and it'd be weird to have them different.

Originally posted by @cholmes in #883 (comment)

Note I'd see an ideal search-update not requiring all the parameters - if you left them off then it'd assume that you want to keep things the same. So like if you just wanted to update the name then you could leave the other values blank. That seems like it'd probably be a complicated implementation, since we'd need to get the JSON and edit the right bits - just putting it here as I think that'd be the ideal experience. But this function is very little used, so not really worth optimizing.