ices/75961.rs: fixed with no errors

[github-actions]

Issue: rust-lang/rust#75961

pub fn foo<'a>(s: &'a mut ()) where &'a mut (): Clone {
    <&mut () as Clone>::clone(&s);
}

fn main() {}

=== stdout ===
=== stderr ===
warning: unused return value of `clone` that must be used
 --> /home/runner/work/glacier/glacier/ices/75961.rs:2:5
  |
2 |     <&mut () as Clone>::clone(&s);
  |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = note: `#[warn(unused_must_use)]` on by default
  = note: cloning is often expensive and is not expected to have side effects

warning: 1 warning emitted

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