Typing-extensions

- Fix regression in v4.12.0 where specialization of certain
generics with an overridden `__eq__` method would raise errors.
Patch by Jelle Zijlstra.
- Fix tests so they pass on 3.13.0b2

- Preliminary changes for compatibility with the draft implementation
of PEP 649 in Python 3.14. Patch by Jelle Zijlstra.
- Fix regression in v4.12.0 where nested `Annotated` types would cause
`TypeError` to be raised if the nested `Annotated` type had unhashable
metadata. Patch by Alex Waygood.

This release is mostly the same as 4.12.0rc1 but fixes one more
longstanding bug.

- Fix incorrect behaviour of `typing_extensions.ParamSpec` on Python 3.8 and
3.9 that meant that
`isinstance(typing_extensions.ParamSpec("P"), typing.TypeVar)` would have a
different result in some situations depending on whether or not a profiling
function had been set using `sys.setprofile`. Patch by Alex Waygood.

This release focuses on compatibility with the upcoming release of
Python 3.13. Most changes are related to the implementation of type
parameter defaults (PEP 696).

Thanks to all of the people who contributed patches, especially Alex
Waygood, who did most of the work adapting typing-extensions to the
CPython PEP 696 implementation.

Full changelog:

- Improve the implementation of type parameter defaults (PEP 696)
- Backport the `typing.NoDefault` sentinel object from Python 3.13.
TypeVars, ParamSpecs and TypeVarTuples without default values now have
their `__default__` attribute set to this sentinel value.
- TypeVars, ParamSpecs and TypeVarTuples now have a `has_default()`
method, matching `typing.TypeVar`, `typing.ParamSpec` and
`typing.TypeVarTuple` on Python 3.13+.
- TypeVars, ParamSpecs and TypeVarTuples with `default=None` passed to
their constructors now have their `__default__` attribute set to `None`
at runtime rather than `types.NoneType`.
- Fix most tests for `TypeVar`, `ParamSpec` and `TypeVarTuple` on Python
3.13.0b1 and newer.
- Backport CPython PR [118774](https://github.com/python/cpython/pull/118774),
allowing type parameters without default values to follow those with
default values in some type parameter lists. Patch by Alex Waygood,
backporting a CPython PR by Jelle Zijlstra.
- It is now disallowed to use a `TypeVar` with a default value after a
`TypeVarTuple` in a type parameter list. This matches the CPython
implementation of PEP 696 on Python 3.13+.
- Fix bug in PEP-696 implementation where a default value for a `ParamSpec`
would be cast to a tuple if a list was provided.
Patch by Alex Waygood.
- Fix `Protocol` tests on Python 3.13.0a6 and newer. 3.13.0a6 adds a new
`__static_attributes__` attribute to all classes in Python,
which broke some assumptions made by the implementation of
`typing_extensions.Protocol`. Similarly, 3.13.0b1 adds the new
`__firstlineno__` attribute to all classes.
- Fix `AttributeError` when using `typing_extensions.runtime_checkable`
in combination with `typing.Protocol` on Python 3.12.2 or newer.
Patch by Alex Waygood.
- At runtime, `assert_never` now includes the repr of the argument
in the `AssertionError`. Patch by Hashem, backporting of the original
fix https://github.com/python/cpython/pull/91720 by Jelle Zijlstra.
- The second and third parameters of `typing_extensions.Generator`,
and the second parameter of `typing_extensions.AsyncGenerator`,
now default to `None`. This matches the behaviour of `typing.Generator`
and `typing.AsyncGenerator` on Python 3.13+.
- `typing_extensions.ContextManager` and
`typing_extensions.AsyncContextManager` now have an optional second
parameter, which defaults to `Optional[bool]`. The new parameter
signifies the return type of the `__(a)exit__` method, matching
`typing.ContextManager` and `typing.AsyncContextManager` on Python
3.13+.
- Backport `types.CapsuleType` from Python 3.13.
- Releases are now made using [Trusted Publishers](https://docs.pypi.org/trusted-publishers/)
improving the security of the release process. Patch by Jelle Zijlstra.

These releases primarily test a revised release workflow. If all goes
well, release 4.12.0rc1 will follow soon.

This feature release provides improvements to various recently
added features, most importantly type parameter defaults (PEP 696).

There are no changes since 4.11.0rc1.