fix: resolve duplicate Example heading anchor

[Divyansh200102]

What kind of change does this PR introduce?
Bugfix

Issue Number:

• Closes 🐛 Bug: HClicking on Example section header scrolls to the first Example section and highlights multiple headers #2343

Summary
Both ### Example headings in non_json_data.md slugified to the same id="example", causing the TOC to always scroll to the first one and highlight both simultaneously.

Fixed by using the existing [#fragment] syntax to give each heading a unique ID (#example-html and #example-base64). No code changes required.

Does this PR introduce a breaking change?
No

Checklist

• Read, understood, and followed the [contributing guidelines](https://github.com/json-schema-org/website/blob/main/CONTRIBUTING.md).

[github-actions]

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (5ca1483) to head (8d8eae6).

Additional details and impacted files

@@            Coverage Diff            @@
##              main     #2350   +/-   ##
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  Coverage   100.00%   100.00%           
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  Files           30        30           
  Lines          672       672           
  Branches       211       211           
=========================================
  Hits           672       672           

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[Divyansh200102]

@Utkarsh-123github why was this one closed was the fix wrong?