fast_io.rs: replace the unsafe libc::copy_file_range call by rustix

[Franklin-Qi]

Replace the unsafe libc::copy_file_range call with the safe rustix::fs::copy_file_range
API to improve safety and reduce unsafe code surface.

Closes: #442

[codecov]

Codecov Report

❌ Patch coverage is 93.33333% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 83.31%. Comparing base (b90c599) to head (bd40e9e).

Files with missing lines	Patch %	Lines
src/sed/fast_io.rs	93.33%	6 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #458      +/-   ##
==========================================
+ Coverage   83.12%   83.31%   +0.18%     
==========================================
  Files          13       13              
  Lines        5885     5939      +54     
  Branches      339      336       -3     
==========================================
+ Hits         4892     4948      +56     
+ Misses        990      988       -2     
  Partials        3        3              

Flag	Coverage Δ
macos_latest	83.80% <100.00%> (+<0.01%)	⬆️
ubuntu_latest	84.06% <93.25%> (+0.18%)	⬆️
windows_latest	0.00% <ø> (ø)

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[sylvestre]

@Franklin-Qi ping ? :)

[sylvestre]

not happy on mac:

error: unused import: `std::os::unix::io::AsFd`
    --> src/sed/fast_io.rs:1053:9
     |
1053 |     use std::os::unix::io::AsFd;
     |         ^^^^^^^^^^^^^^^^^^^^^^^
     |
     = note: `-D unused-imports` implied by `-D warnings`
     = help: to override `-D warnings` add `#[allow(unused_imports)]`

[Franklin-Qi]

Thanks for the feedback; I’ve modified the compilation conditions. I don’t have a Mac here, so please take a look.