[Request] Mojo

I'd love to see [Mojo](https://en.wikipedia.org/wiki/Mojo_(programming_language)) added. I was looking for introductions to the language, and Learn X in Y Minutes was my first stop.

Existing material I have found:

- [Mojo by Example](https://ruhati.net/mojo/)
- [Mojo Quest](https://quest.mojolang.org/)

No file paths or tests are provided, so first inspect the repository’s existing language pages and any index/readme that enumerates them. Identify where new language tutorial entries are added and linked, then follow the same pattern to add Mojo content in Markdown. Keep consistency with neighboring tutorials and links. Done when Mojo appears as an available guide in the same navigation and listing as other languages.

Written by the indexing model from the issue text.