fix(3.12_generics_syntax): Fixed formatting of 3.12 generics syntax (#4777)

* fix(3.12_generics_syntax): Fixed formatting of 3.12 generics syntax

* chore: add test cases and update CHANGELOG

* revert: Formatted test code files, Im dumb

* chore: update with multiple tests

* fix: Use PR number instead of issue

* chore: move fix to preview with proper documentation for stability

* chore: update linegen to check against mode

Co-authored-by: GiGaGon <107241144+MeGaGiGaGon@users.noreply.github.com>

* chore: update changes.md to move it to preview

* fix: minimum python version to 3.12 for tests

* Fix changelog entry

* Update type_params.py to remove unnecessary edit

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Co-authored-by: GiGaGon <107241144+MeGaGiGaGon@users.noreply.github.com>