* `mlir.ir` now exports `_OperationBase`. It is handy to use when both
`Operation` and `OpView` are accepted.
* Added type arguments where they were missing, e.g.
`list[ir.Attribute]` instead of just `list`.
* Changed `Opview.build_generic` and `OpView.parse` to return `Self`
instead of the supertype `Type`.
* Changed the bindings generator to emit a parameterized `OpResult` when
the exact type is available.
396d63813c