CSTNode.with_deep_changes type annotation is incomplete

For example, I want to replace all args of a `Call`:

```
node.with_deep_changes(
old_node=cst.ensure_type(node.value, cst.Call).args, value=[input_arg]
)
```

The code works fine, but the type checker complains:
error: Argument "old_node" to "with_deep_changes" of "CSTNode" has incompatible type "Sequence[Arg]"; expected "CSTNode"