Consider adding typealiases for Operations.*.Input.* types for referenced types

When all types are inline, you get consistent names for all operations:

* `Operations..Input.Path`
* `Operations..Input.Query`
* `Operations..Input.Headers`
* `Operations..Input.Cookies`
* `Operations..Input.Body`

And similar for `Operations..Output`.

When using reusable types for `requestBody`, `parameter`, and `response`, however, these can point directly to e.g. `Components.RequestBodies.Foo`, etc, which breaks the symmetry.

Consider emitting a typealias here that would make all the names predictable, e.g.

```swift
enum Operations {
enum {
struct Input {
typealias Body = Components.RequestBodies.Foo
}
}
}
```

Start by locating the generator paths that emit Operations..Input and Output types for inline and reusable requestBody, parameter, and response types. Compare their naming behavior and identify the relevant generation tests; done when reusable references also expose predictable typealiases without changing the referenced types.

Written by the indexing model from the issue text.