Fix Incorrect Test File Link in Recursion README.md

[paulallensuxs]

Description

Problem*

The test file link in the README.md of the recursion folder within the noir-examples repository was incorrect, pointing to a non-existing path. This made it difficult for users to locate and run the test file as instructed.

Summary*

This Pull Request updates the README.md file in the recursion folder to correct the path to the test file. The link has been updated from ./test/index.ts to ./packages/hardhat/test/index.test.ts, reflecting the actual location of the test file within the repository structure.

Additional Context

This change makes sure that contributors and users can correctly access and run the test file as described in the README.md, improving the developer experience.

PR Checklist*

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt on default settings.

[critesjosh]

thanks!