Fix Clippy lint for 1.88.0 (clippy::neg_multiply)

[patowen]

warning: this multiplication by -1 can be written more succinctly
   --> common\src\plane.rs:144:13
    |
144 |             root.distance_to_chunk(Vertex::J, &na::Vector3::new(-1.0, 1.0, 1.0)) * -1.0,
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `-root.distance_to_chunk(Vertex::J, &na::Vector3::new(-1.0, 1.0, 1.0))`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#neg_multiply
    = note: `#[warn(clippy::neg_multiply)]` on by default