add async Retry __eq__ and __hash__ & fix ExponentialWithJitterBackoff __eq__

[terencehonles]

Description of change

This change fixes a typo in ExponentialWithJitterBackoff's __eq__ method from #3628, and allows async Retry objects to also support __eq__ and __hash__.

Pull Request check-list

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[petyaslavova]

I think that we don't need to use __slots__ for the retry object. We are not keeping that many instances of it, and the saved memory is not going to be significant. I see that we've had both patterns in the sync and async versions, and I suggest sticking to the one that has been used by the sync Retry class.

[petyaslavova]

I think it would be better here if you extract the list as a constant and assign this list as the default value - it will be more visible what will be assigned to the list in case the user doesn't provide a value.

[petyaslavova]

I think we should have __eq__ implemented in each class(sync and async) and check if it is an instance of the concrete classes.

[Copilot]

Pull Request Overview

This PR fixes the equality comparison in ExponentialWithJitterBackoff and extends support for eq and hash to async Retry objects. It also refactors the Retry code into an abstract base class and updates the async retry implementation accordingly.

• Updated tests to parameterize both sync and async Retry objects.
• Refactored the Retry class into AbstractRetry with a subclass, and corrected the equality check for ExponentialWithJitterBackoff.
• Modified the async Retry class to inherit from AbstractRetry and revised the type hint for the fail callback.

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
tests/test_retry.py	Updated tests to cover both sync and async Retry equality and hash.
redis/retry.py	Refactored Retry into AbstractRetry and fixed supported_errors handling in eq.
redis/backoff.py	Corrected the equality check to validate against the appropriate class.
redis/asyncio/retry.py	Changed Retry to subclass AbstractRetry and adjusted the fail callback type.

Comments suppressed due to low confidence (2)

redis/retry.py:34

• If supported_errors is not provided, _supported_errors is never set, which could lead to an AttributeError during equality checks. Consider initializing _supported_errors to a default value (e.g., an empty tuple) when supported_errors is None.

if supported_errors:

redis/asyncio/retry.py:17

• Changing the type for the fail callback from RedisError to Exception broadens the error types handled. Confirm that this change is intentional to avoid inadvertently catching non-Redis errors.

self, do: Callable[[], Awaitable[T]], fail: Callable[[Exception], Any]