Removed Markdown Ninja announcement

Removed announcement about Markdown Ninja from Project/Tooling Updates section as it isn't a project/tool for Rust or written in Rust (it's written in Go and Vue mostly)

Author: chris-t-jansen

draft/2025-05-21-this-week-in-rust.md

@@ -41,7 +41,6 @@ and just ask the editors to select the category.
 ### Newsletters
 
 ### Project/Tooling Updates
-* [Announcing Markdown Ninja: Open Source alternative to Substack, Mailchimp and Netlify](https://kerkour.com/announcing-markdown-ninja)
 * [Hypervisor as a Library](https://seiya.me/blog/hypervisor-as-a-library)
 
 ### Observations/Thoughts