ruff

1f7a29d3 - [red-knot] Unpacker: Make invariant explicit and directly return a Type (#16018)

[red-knot] Unpacker: Make invariant explicit and directly return a Type (#16018) ## Summary - Do not return `Option<Type<…>>` from `Unpacker::get`, but just `Type`. Panic otherwise. - Rename `Unpacker::get` to `Unpacker::expression_type`