Switch display names for numadults_mom and numchildren_mom

[mrueschman]

Display names (labels) must have been transposed. Noted and reported by a user. Confirmed in the dataset (children ~= 0.7; adults ~= 1.3).

https://sleepdata.org/datasets/shine/variables/numadults_mom
https://sleepdata.org/datasets/shine/variables/numchildren_mom