Add missing type hints for all flavors of LayoutLMv2 PyTorch models.
# What does this PR do?

I added type hints for all `LayoutLMv2` PyTorch classes as described in https://github.com/huggingface/transformers/issues/16059 .

@Rocketknight1 


This also looks good, but same comment about the return types!<|||||>_The documentation is not available anymore as the PR was closed or merged._<|||||>> This also looks good, but same comment about the return types!

Yes I fixed return types + I added all type hints for `LayoutLM` PyTorch <|||||>Hi, I'm seeing some tests failing on this one - I think you might have deleted a couple of arguments while adding the annotations!