Update json.md

[vlrnsnk]

Remove trailing commas on pseudocode JSON

Description

Issue Solved

Type of Change

• 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.

[vlrnsnk]

@yoiang hi, please, assign me to this one.

[mamtawardhani]

Thank you for contributing to Codecademy Docs @vlrnsnk 😄

The entry looks good for a second round of review! 🚀

[vlrnsnk]

@yoiang can you please review it?