fix an incorrect indent in documentation (#108273)
doc for `torch.distributed.send(tensor, dst, group=None, tag=0)` was rendering incorrectly here: https://pytorch.org/docs/stable/distributed.html due to lack of indent (it was interpreting the continuation as a new argument).
Pull Request resolved: https://github.com/pytorch/pytorch/pull/108273
Approved by: https://github.com/awgu, https://github.com/kit1980
