Improved log1p implementation for complex inputs (#107100)
This PR improves the implementation of `torch.log1p` for complex inputs as mentioned in issue #107022. The new implementation is based on the insights provided in https://github.com/numpy/numpy/pull/22611#issuecomment-1667945354.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/107100
Approved by: https://github.com/lezcano
