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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• Do tests and lints pass with this change?
• Do the CI tests pass with this change (enable it first in your forked repo and wait for the github action build to finish)?
• Is the new or changed code fully tested?
• Is a documentation update included (if this change modifies existing APIs, or introduces new ones)?
• Is there an example added to the examples folder (if applicable)?

NOTE: these things are not required to open a PR and can be done
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[Copilot]

Pull Request Overview

This PR fixes a typo in the ExponentialWithJitterBackoff.__eq__ method and refactors the retry system to support __eq__ and __hash__ methods for async Retry objects. The changes introduce a shared base class to eliminate code duplication between sync and async retry implementations.

• Extracts common retry functionality into an AbstractRetry base class with generic type support
• Fixes incorrect class name check in ExponentialWithJitterBackoff.__eq__ method
• Updates tests to verify both sync and async Retry objects support equality and hashing operations

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
redis/retry.py	Refactors to introduce AbstractRetry base class and updates Retry to inherit from it
redis/asyncio/retry.py	Simplifies async Retry by inheriting from AbstractRetry and implementing __eq__ method
redis/backoff.py	Fixes typo in ExponentialWithJitterBackoff.__eq__ method class name check
tests/test_retry.py	Parameterizes existing tests to cover both sync and async Retry classes

[Copilot]

[nitpick] Manually copying docstrings can lead to maintenance issues. Consider using proper inheritance or decorators to share documentation, or simply let the docstring inherit naturally from the parent class.

Suggested change

__init__.__doc__ = AbstractRetry.__init__.__doc__

[terencehonles]

I removed both of these, but I'm not sure this is actually correct. This is supposed to be the case for class docstrings, but this is a class method and testing locally (I wasn't sure of this before the review and tested myself) it did not inherit the docstring (at least when using the help method).