Issue 32 lint unsafe

[ivanitskiy]

Proposed changes

this PR complements changes from https://github.com/nginxinc/ngx-rust/pull/38.

Checklist

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• [x] I have written my commit messages in the Conventional Commits format.
• [x] I have read the CONTRIBUTING doc
• [x] I have added tests (when possible) that prove my fix is effective or that my feature works
• [x] I have checked that all unit tests pass after adding my changes
• [x] I have updated necessary documentation
• [x] I have rebased my branch onto master
• [x] I will ensure my PR is targeting the main branch and pulling from my branch from my own fork