[PyTorch] Add doc string for lite interpreter related api in Android (#53136)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/53136
As title, doc string in ios, c++ and python is ready.
As a reference, the doc string for other lite interpreter related apis
[_load_for_mobile](https://www.internalfb.com/intern/diffusion/FBS/browsefile/master/fbcode/caffe2/torch/csrc/jit/mobile/import.h?commit=c95d12f9d67ee198aa4b5aafec980e9048de1702&lines=16-43)
[_save_for_lite_interpreter](https://www.internalfb.com/intern/diffusion/FBS/browsefile/master/fbcode/caffe2/torch/jit/_script.py?commit=b1d7f0ba6001beed6ba3b0a69a225abab4ed3866&lines=496-509)
ghstack-source-id: 122936777
Test Plan: CI
Reviewed By: IvanKobzarev, iseeyuan
Differential Revision: D26742092
fbshipit-source-id: 76464b5e4ceafe71348b58ba2af98c3debdaae63
