docs: add missing } and remove comma (#9223)

### Description

- ~~The JSON code block's indentation has been corrected for better
readability and proper JSON structure~~
- ~~Added the `inputs` property to `build` to match the actual
[turbo.json](https://github.com/vercel/turborepo/blob/053a46031df7970059e458d3cc705f11b1daf313/examples/basic/turbo.json#L7)
content~~
- Added a missing `}` to the JSON code block and removed a trailing
comma

### Testing Instructions

<!--
  Give a quick description of steps to test your changes.
-->

docs/repo-docs/crafting-your-repository/creating-an-internal-package.mdx

@@ -264,7 +264,8 @@ Add the artifacts for the new `@repo/math` library to the `outputs` for the `bui
   "build": {
     "dependsOn": ["^build"],
     "outputs": [".next/**", "!.next/cache/**", "dist/**"]
-  },
+  }
+}
 }
 ```