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>

docs/repo-docs/crafting-your-repository/structuring-a-repository.mdx

@@ -332,7 +332,7 @@ Using exports this way provides three major benefits:
 </Tab>
 
 <Tab value="multiply.ts">
-```ts title="./packages/math/src/add.ts"
+```ts title="./packages/math/src/multiply.ts"
 import { add } from "#add";
 
 export const multiply = (a: number, b: number) => {