chore(style): apply Clippy suggestion

Author: samueltardieu

src/directed/idastar.rs

@@ -139,7 +139,7 @@ where
                 })
             })
             .collect::<Vec<_>>();
-        neighbs.sort_unstable_by(|(_, _, c1), (_, _, c2)| c1.cmp(c2));
+        neighbs.sort_unstable_by_key(|(_, _, c1)| *c1);
         neighbs
     };
     let mut min = None;