Replication of original PR #582: Add Reader and Writer protocols

[yashwanthatla]

PR Summary

Add Reader and Writer Protocol Classes to typing_extensions

Overview

This PR adds new Reader and Writer Protocol classes to the typing_extensions module, with a fallback mechanism that checks if the io module already has these classes.

Change Types

Type	Description
Feature	Add Reader and Writer Protocol classes
Test	Add tests for new protocol classes

---

Affected Modules

Module / File	Change Description
typing_extensions.py	Add Reader and Writer Protocol classes with fallback mechanism
typing_extensions.py	Import io module to support new protocol classes
typing_extensions.py	Add 'Reader' and 'Writer' to all list
test_typing_extensions.py	Add SpecificProtocolTests class with tests for new protocols
conf.py	Update Python documentation reference URL and add comments

Notes for Reviewers

• The implementation includes a fallback mechanism that checks if the io module already has these classes
• The protocols are runtime checkable

[codeowlai]

🐛 Correctness Issue

Reference to non-existent Python version 3.14.

The intersphinx_mapping points to Python 3.14 documentation which doesn't exist yet, causing broken documentation links and build failures.

Current Code (Diff):

- intersphinx_mapping = {'py': ('https://docs.python.org/3.14', None)}
+ intersphinx_mapping = {'py': ('https://docs.python.org/3', None)}

📝 Committable suggestion

‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

Suggested change

	intersphinx_mapping = {'py': ('https://docs.python.org/3.14', None)}
	intersphinx_mapping = {'py': ('https://docs.python.org/3', None)}