Reintroducing use of byCombo

[megoth]

Should fix SolidOS/solid-panes#193

[Vinnl]

Happy to go ahead with this now, but since it does change doingDefault to doingDefaults and neither of us has any idea what it's supposed to do, it would be good if @timbl could take a look at it still after merging.

[megoth]

I cannot find any use of doingDefaults outside of solid-ui and no use of doingDefault at all (and I've checked all projects connected to the data browser). But yes, there might be other projects that use this API that uses doingDefault, so we'll double-check with @timbl .

[Vinnl]

I wasn't really talking about other projects, just that the code you just put back used to refer to doingDefault (which didn't exist) - so whatever that code was supposed to do, it never did it, but it will likely now start doing it. I have no idea about whether that's desirable or not.