New review comment by TinfoilSubmarine on void-packages repository

https://github.com/void-linux/void-packages/pull/39416#discussion_r980225145

Comment:
It is a required runtime dependency. Running without it gives:
```
ERROR:root:Synapse 1.68.0rc2 needs setuptools_rust, but it is not installed
Missing Requirements: "setuptools_rust"
To install run:
    pip install --upgrade --force "setuptools_rust"
```

See https://github.com/matrix-org/synapse/blob/682385917dd8d3c877da109c4cdc0988073b5b00/pyproject.toml#L185