Add Pythonlings to Python resources

[abhiksark]

Summary

Add Pythonlings to Python > Resources. It is a free, MIT-licensed terminal learning tool with 292 fix-and-verify exercises across 31 Python topics.

The change adds one resource in the required name, link, and brief-description format. It is placed beside the existing Interactive Coding Challenges entry. Searches of the default branch, open and closed issues, pull requests, and the suggestions thread found no duplicate.

Disclosure

I maintain Pythonlings and am submitting my own project for consideration. The current release is v0.4.2, and the project describes itself as alpha.

Validation

• git diff --check
• Confirmed the project URL returns HTTP 200.
• Installed docs/requirements.txt in an isolated virtual environment.
• Reproduced the workflow README preparation and ran make -C docs html; the Sphinx build succeeded.