The second set of lecture notes on neural networks contains an inaccuracy regarding hierarchical softmax. This pull request fixes it by clarifying the use cases of hierarchical softmax.
The second set of lecture notes on neural networks contains an
inaccuracy regarding hierarchical softmax. This pull request fixes it by
clarifying the use cases of hierarchical softmax.

cs231n/cs231n.github.io,cs231n/cs231n.github.io,cs231n/cs231n.github.io