Use mypy 1.11 features: `--enable-incomplete-feature=NewGenericSyntax`

[hf-kklein]

from the release notes (#93)

Support Python 3.12 Syntax for Generics (PEP 695)

Mypy now supports the new type parameter syntax introduced in Python 3.12 (PEP 695). This feature is still experimental and must be enabled with the --enable-incomplete-feature=NewGenericSyntax flag, or with enable_incomplete_feature = NewGenericSyntax in the mypy configuration file. We plan to enable this by default in the next mypy feature release.

maybe we should enables this here?