generated_* files seem to throw ides for a loop

VSCode + rust-analyzer does far worse at things like jump to definition on the generated_X files. For example, in generated_layout.rs you can't go to definition on the struct for the enum formats here:

```rust
#[derive(Clone, Debug)]
pub enum ChainedSequenceContext {
Format1(ChainedSequenceContextFormat1),
Format2(ChainedSequenceContextFormat2),
Format3(ChainedSequenceContextFormat3),
}
```

I suspect the use via include! might be related. Could we generate them but have them act more like handwritten files, notably *not* use include! to pull them in?

This slowed me down considerably when confused about how some of the layout types and macros worked.