Add chatmode to address PR comments

[AmeliaRose802]

Pull Request Checklist

• I have read and followed the CONTRIBUTING.md guidelines.
• My contribution adds a new instruction, prompt, or chat mode file in the correct directory.
• The file follows the required naming convention.
• The content is clearly structured and follows the example format.
• I have tested my instructions, prompt, or chat mode with GitHub Copilot.
• I have run node update-readme.js and verified that README.md is up to date.

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Description

I've been using this chatmode locally for a while and found that it works very well for addressing PR comments. It makes limited scope changes that address the specific comment which helps prevent it from breaking other things.

It will try to add test coverage for it's fixes and will commit each change.

I typically use this mode is combination with my reviewer mode however, I've also tested it with human written code and it performs well.

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Type of Contribution

• New instruction file.
• New prompt file.
• New chat mode file.
• Other (please specify):

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Additional Notes

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By submitting this pull request, I confirm that my contribution abides by the Code of Conduct and will be licensed under the MIT License.