+kids:of should probably return an axal

[bonbud-macryg]

+kids is the only arm in the +of core that returns an +axil rather than an +axal. This makes it hard to get a map-like subtree from the shrub's kids or deps without doing something like ~(tar of:neo (~(del of:neo q:(~(got by deps.bowl) %src)) /))), which could just be ~(kids of:neo q:(~(got by deps.bowl) %src)).

I naively tried changing this but hit error -find.kid.fat when I tried to run +tar:of on the output of +kids:of, suggesting that its output wasn't an axal.

It's worth noting that there are two +kids:of arms in /sur/neo.hoon. Changing either or both of these arms to return an +axal resulted in the error above.

I asked Liam if there was a reason +kids:of returns an +axil and he couldn't recall.