Docs: examples page -> gt-extras example

[juleswg23]

Summary

This PR adds a gt-extras example to the examples page, at the bottom in a new section called "ecosystem."

Related GitHub Issues and PRs

• Ref: #

Checklist

• I understand and agree to the Code of Conduct.
• I have followed the Style Guide for Python Code as best as possible for the submitted code.
• I have added pytest unit tests for any new functionality.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.23%. Comparing base (18321f1) to head (11f96f1).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #759   +/-   ##
=======================================
  Coverage   92.23%   92.23%           
=======================================
  Files          48       48           
  Lines        5875     5875           
=======================================
  Hits         5419     5419           
  Misses        456      456           

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