Introduce new type for RESP3 PUSH notifications

[uglide]

Allow clients to distinguish between RESP3 arrays and PUSH types by introducing PushNotification type, which subclasses list.

Fix #128

[Copilot]

Pull Request Overview

This pull request introduces a new PushNotification type to distinguish RESP3 PUSH notifications from regular RESP3 arrays. Key changes include:

• Adding type definitions and implementations for PushNotification in both C headers and source files.
• Updating the module initialization to export the new type.
• Extending tests and type stubs to verify and document the new PushNotification functionality.

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
tests/test_reader.py	Introduces tests to check if reader.gets() returns an instance of PushNotification.
src/reader.h	Declares the PushNotificationObject struct and external PushNotificationType variable.
src/reader.c	Implements PushNotificationType initialization and creation with preallocated size.
src/hiredis.c	Sets the PushNotificationType base as PyList_Type and adds it to the module exports.
hiredis/hiredis.pyi	Defines the PushNotification type in the type stubs.
hiredis/init.py	Exports the PushNotification type as part of the module's public API.

[Copilot]

For a zero-element PushNotification (i.e., when size == 0), the ob_item field is not explicitly initialized. Consider initializing ob_item to a valid empty list pointer to ensure proper list behavior.