Clippy: Replace min/max calls with clamp

[rubdos]

No significant difference in performance (laptop was a bit warm towards the end anyway)

Benchmarking decode LGF5]+Yk^6#M@-5c,1J5@[or[Q6./200: Collecting 100 samples in estimated 5.decode LGF5]+Yk^6#M@-5c,1J5@[or[Q6./200
                        time:   [2.9601 ms 2.9679 ms 2.9769 ms]
                        change: [-0.5812% -0.2357% +0.1341%] (p = 0.20 > 0.05)
                        No change in performance detected.
Found 14 outliers among 100 measurements (14.00%)
  4 (4.00%) high mild
  10 (10.00%) high severe

Benchmarking decode_into LGF5]+Yk^6#M@-5c,1J5@[or[Q6./200: Collecting 100 samples in estimatdecode_into LGF5]+Yk^6#M@-5c,1J5@[or[Q6./200
                        time:   [2.9857 ms 2.9965 ms 3.0077 ms]
                        change: [+0.2166% +0.6813% +1.1576%] (p = 0.01 < 0.05)
                        Change within noise threshold.
Found 1 outliers among 100 measurements (1.00%)
  1 (1.00%) high mild

     Running benches/encode.rs (target/release/deps/encode-a9d404ceb3500bd9)
Benchmarking encode data/octocat.png: Collecting 100 samples in estimated 5.2636 s (1800 iteencode data/octocat.png time:   [2.9249 ms 2.9315 ms 2.9389 ms]
                        change: [+2.3760% +2.6619% +2.9393%] (p = 0.00 < 0.05)
                        Performance has regressed.
Found 16 outliers among 100 measurements (16.00%)
  16 (16.00%) high severe