chore: update title in multiply.ts file in docs (#8911)
### Description
It just fixes the file title in [Structuring a
repository](https://turbo.build/repo/docs/crafting-your-repository/structuring-a-repository#getting-started)
section of the docs.
Typo:
https://github.com/user-attachments/assets/2bde1464-12b2-4622-8aef-47d6fa82f6b5
Co-authored-by: Thomas Knickman <tom.knickman@vercel.com>
