cargo fmt and cargo clippy

Dependencies

• [2] J5J4TGTH Part 2 for 2021 day 4
• [3] P7M5N7HR Part 1 solution for 2021 day 4

Change contents

• replacement in 2021/day4.rs at line 28
  [3.853]→[3.853:870](∅→∅)
  − ) -> usize {
  [3.853]

  [3.870]
  + ) -> usize {
• replacement in 2021/day4.rs at line 48
  [3.1296]→[2.0:119](∅→∅)
  − fn parse_boards<'a, I: Iterator<Item = S>, S: AsRef<str>>(input: &'a mut I) -> impl Iterator<Item=Vec<Vec<u8>>> + 'a {
  [3.1296]

  [3.1388]
  + fn parse_boards<I: Iterator<Item = S>, S: AsRef<str>>(

  + input: &mut I,

  + ) -> impl Iterator<Item = Vec<Vec<u8>>> + '_ {
• replacement in 2021/day4.rs at line 52
  [3.1398]→[3.1398:1440](∅→∅)
  − .filter(|l| l.as_ref().len() > 0)
  [3.1398]

  [3.1440]
  + .filter(|l| !l.as_ref().is_empty())
• replacement in 2021/day4.rs at line 80
  [2.211]→[2.211:256](∅→∅)
  − let (score1,step1,score2,step2) = boards
  [2.211]

  [3.2305]
  + let (score1, step1, score2, step2) = boards
• replacement in 2021/day4.rs at line 83
  [3.2412]→[3.2412:2497](∅→∅)
  − (score_board(&draws,board.iter().map(|r| r.iter().copied()),step), step)
  [3.2412]

  [3.2497]
  + (

  + score_board(&draws, board.iter().map(|r| r.iter().copied()), step),

  + step,

  + )
• replacement in 2021/day4.rs at line 88
  [3.2508]→[2.257:499](∅→∅)
  − .fold(None, |acc, (score,step)| match acc {

  − None => Some((score,step,score,step)),

  − Some((score1,step1,score2,step2)) => {

  − let (score1,step1) = if step < step1 {

  − (score,step)
  [3.2508]

  [2.499]
  + .fold(None, |acc, (score, step)| match acc {

  + None => Some((score, step, score, step)),

  + Some((score1, step1, score2, step2)) => {

  + let (score1, step1) = if step < step1 {

  + (score, step)
• replacement in 2021/day4.rs at line 94
  [2.524]→[2.524:559](∅→∅)
  − (score1,step1)
  [2.524]

  [2.559]
  + (score1, step1)
• replacement in 2021/day4.rs at line 96
  [2.578]→[2.578:666](∅→∅)
  − let (score2,step2) = if step > step2 {

  − (score,step)
  [2.578]

  [2.666]
  + let (score2, step2) = if step > step2 {

  + (score, step)
• replacement in 2021/day4.rs at line 99
  [2.691]→[2.691:726](∅→∅)
  − (score2,step2)
  [2.691]

  [2.726]
  + (score2, step2)
• replacement in 2021/day4.rs at line 101
  [2.745]→[2.745:795](∅→∅)
  − Some((score1,step1,score2,step2))
  [2.745]

  [2.795]
  + Some((score1, step1, score2, step2))
• replacement in 2021/day4.rs at line 108
  [2.917]→[2.917:1008](∅→∅)
  − let (last_called,_) = draws.iter().filter(|(_,step)| **step == step1).next().unwrap();
  [2.917]

  [3.2748]
  + let (last_called, _) = draws.iter().find(|(_, step)| **step == step1).unwrap();
• replacement in 2021/day4.rs at line 115
  [2.1182]→[2.1182:1273](∅→∅)
  − let (last_called,_) = draws.iter().filter(|(_,step)| **step == step2).next().unwrap();
  [2.1182]

  [2.1273]
  + let (last_called, _) = draws.iter().find(|(_, step)| **step == step2).unwrap();
• edit in 2021/day4.rs at line 118
  [2.1380]→[2.1380:1381](∅→∅)
  −
• replacement in 2021/day4.rs at line 143
  [3.3505]→[3.3505:3540](∅→∅)
  − if result.len() == 0 {
  [3.3505]

  [3.3540]
  + if result.is_empty() {