Typeguard

- Fixed ``typing_extensions`` being imported unconditionally on Python < 3.9
(bug introduced in 2.13.1)

- Fixed ``typechecked`` replacing abstract properties with regular properties
- Fixed any generic type subclassing ``Dict`` being mistakenly checked as ``TypedDict`` on
Python 3.10

- Added support for returning ``NotImplemented`` from binary magic methods (``__eq__()`` et al)
- Added support for checking union types (e.g. ``Type[Union[X, Y]]``)
- Fixed error message when a check against a ``Literal`` fails in a union on Python 3.10
- Fixed ``NewType`` not being checked on Python 3.10
- Fixed unwarranted warning when ``typechecked`` is applied to a class that contains unannotated
properties
- Fixed ``TypeError`` in the async generator wrapper due to changes in ``__aiter__()`` protocol
- Fixed broken ``TypeVar`` checks – variance is now (correctly) disregarded, and only bound types
and constraints are checked against (but type variable resolution is not done)

- Fixed ``AttributeError`` when ``__code__`` is missing from the checked callable (PR by epenet)

- Added ``typeguard_ignore`` decorator to exclude specific functions and classes from
runtime type checking (PR by Claudio Jolowicz)

- Fixed compatibility with Python 3.10