Update benchmark and fix lint

Author: maneatingape

README.md

@@ -263,7 +263,7 @@ Performance is reasonable even on older hardware, for example a 2011 MacBook Pro
 | Day | Problem | Solution | Benchmark (μs) |
 | --- | --- | --- | --: |
 | 1 | [Chronal Calibration](https://adventofcode.com/2018/day/1) | [Source](src/year2018/day01.rs) | 16 |
-| 2 | [Inventory Management System](https://adventofcode.com/2018/day/2) | [Source](src/year2018/day02.rs) | 78 |
+| 2 | [Inventory Management System](https://adventofcode.com/2018/day/2) | [Source](src/year2018/day02.rs) | 56 |
 | 3 | [No Matter How You Slice It](https://adventofcode.com/2018/day/3) | [Source](src/year2018/day03.rs) | 55 |
 | 4 | [Repose Record](https://adventofcode.com/2018/day/4) | [Source](src/year2018/day04.rs) | 46 |
 | 5 | [Alchemical Reduction](https://adventofcode.com/2018/day/5) | [Source](src/year2018/day05.rs) | 390 |

src/year2018/day02.rs

@@ -58,7 +58,7 @@ pub fn part2(input: &[&[u8]]) -> String {
 
             if !seen.insert([prefix, suffix]) {
                 // Convert to String
-                return prefix.iter().chain(suffix).cloned().map(char::from).collect();
+                return prefix.iter().chain(suffix).copied().map(char::from).collect();
             }
         }