q-rng data.frame printing error

[dsweber2]

While stepping through the predict layer for quantile_reg, I kept getting errors trying to print a data.frame containing q-rng distributions. The error is Error in round(rng[1], digits) : invalid second argument of length 0. It prints fine as a vctrs_vctr when I select the corresponding column, though the output isn't very informative (a vector consisting of [0.01, 0.99]<q-rng>).

Sorry if this is a more obscure description than usual, as its hard to actually see the contents to reproduce.

[dajmcdon]

possibly fixed by #243