The `parse-hosts` crate was recently updated so that it doesn't use any unstable features.
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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [X] These changes do not require tests because tests were already implemented.
Source-Repo: https://github.com/servo/servo
Source-Revision: eec51cdd575cf985bc1ed926c6cb8868f1ba0e0e