docs: Add PyTorch .polygamma() tensor operation documentation

[Priyanshjain10]

Created comprehensive documentation entry for PyTorch's .polygamma() tensor operation function including:

• Complete front matter with metadata (subjects, tags, catalog content)
• Clear definition explaining the polygamma function
• Detailed syntax section with parameter descriptions
• Three practical code examples:
  • Digamma function (n=0)
  • Trigamma function (n=1)
  • Higher order polygamma (n=2)
• Usage notes for statistical applications
• Links to related tensor operation functions

This documentation follows Codecademy's term entry template and markdown style guide.

Fixes #7849
Submitted for Hacktoberfest 2025.

Description

Issue Solved

Type of Change

• Adding a new entry
• Editing an existing entry (fixing a typo, bug, issues, etc)
• Updating the documentation

Checklist

• All writings are my own.
• My entry follows the Codecademy Docs style guide.
• My changes generate no new warnings.
• I have performed a self-review of my own writing and code.
• I have checked my entry and corrected any misspellings.
• I have made corresponding changes to the documentation if needed.
• I have confirmed my changes are not being pushed from my forked main branch.
• I have confirmed that I'm pushing from a new branch named after the changes I'm making.
• I have linked any issues that are relevant to this PR in the Issues Solved section.

[CLAassistant]

All committers have signed the CLA.

[mamtawardhani]

Looks good for a second review! 🚀

[Priyanshjain10]

Thank you @mamtawardhani for the thorough review and approval! 🙏 Really appreciate your time and feedback. Working on statistical functions like polygamma has been fascinating, and I'm excited to document more PyTorch operations. Happy to be part of the Codecademy community and contribute to making these advanced mathematical concepts easier to understand for learners worldwide! Looking forward to more collaborations! 🚀

[dakshdeepHERE]

LGTM 🚀

[github-actions]

👋 @Priyanshjain10
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[Priyanshjain10]

🎉 Thank you so much @mamtawardhani and @dakshdeepHERE for merging this PR! I'm excited that the PyTorch .polygamma() documentation is now live!

I really appreciate your thorough reviews and for taking the time to merge all my contributions. Your guidance has been incredibly helpful and I'm learning so much from this process.

Looking forward to continuing to contribute to Codecademy Docs! 🚀🙏