C++ API: torch::nn::LogSoftmax (#27462)
Summary:
Add torch::nn::LogSoftmax module and functional support for the C++ API.
Related Issue: https://github.com/pytorch/pytorch/issues/25883
Reviewer: yf225
Pull Request resolved: https://github.com/pytorch/pytorch/pull/27462
Differential Revision: D17867121
Pulled By: yf225
fbshipit-source-id: dae8ac981c1c6ccdef013cd2d886ad4a043f6243
