🐛 Bug: README.md additional content should ignore older "this package is based on" notices

[JoshuaKGoldberg]

Bug Report Checklist

• I have tried restarting my IDE and the issue persists.
• I have pulled the latest main branch of the repository.
• I have searched for related issues and found none that matched my issue.

Expected

Older CTA repos used "templated by" notice like:

> 💙 This package is based on [@JoshuaKGoldberg](https://github.com/JoshuaKGoldberg)'s [create-typescript-app](https://github.com/JoshuaKGoldberg/create-typescript-app).

This should be omitted when running npx create-typescript-app in transition mode

Actual

https://github.com/JoshuaKGoldberg/should-semantic-release/pull/547/files#r2026952619: it's not.

Additional Info

🎁

[github-actions]

🎉 This is included in version v2.24.2 🎉

The release is available on:

• GitHub releases
• npm package (@latest dist-tag)

Cheers! 📦🚀