Fix missing rz prefix for set_s_free

[pelijah]

Your checklist for this pull request

• [ ] I've read the guidelines for contributing to this repository
• [ ] I made sure to follow the project's coding style
• [ ] I've documented or updated the documentation of every function and struct this PR changes. If not so I've explained why.
• [ ] I've added tests that prove my fix is effective or that my feature works (if possible)
• [ ] I've updated the rizin book with the relevant information (if needed)

Detailed description

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Test plan

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Closing issues

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