Rust Toolchain: Upgrade to rust edition 2024

[eval-exec]

• rust-toolchain: upgrade rust edition to 2021
• **clippy: Using mem::take is faster as it avoids the allocation: https://rust-lang.github.io/rust-clippy/master/index.html#drain_collect

warning: you seem to be trying to move all elements into a new `Vec`
   --> src/mmr.rs:501:5
    |
501 |     v.drain(..).collect()
    |     ^^^^^^^^^^^^^^^^^^^^^ help: consider using `mem::take`: `std::mem::take(v)`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#drain_collect
    = note: `#[warn(clippy::drain_collect)]` on by default

• rust-toolchain: upgrade rust 2024
• execute cargo fmt --all
• set MSCV to 1.85.0

[eval-exec]

Hello, @quake , please re-trigger the CI workflows.

[eval-exec]

On Intel i9-14900K,
master branch:

     Running benches/helper_benchmark.rs (target/release/deps/helper_benchmark-b5e33b9f7196d37d)
Gnuplot not found, using plotters backend
left_index_to_pos       time:   [10.147 ns 10.167 ns 10.190 ns]
Found 7 outliers among 100 measurements (7.00%)
  3 (3.00%) high mild
  4 (4.00%) high severe

left_index_to_mmr_size  time:   [10.103 ns 10.125 ns 10.151 ns]
Found 6 outliers among 100 measurements (6.00%)
  2 (2.00%) high mild
  4 (4.00%) high severe

     Running benches/mmr_benchmark.rs (target/release/deps/mmr_benchmark-2b195913ce62bb0e)
Gnuplot not found, using plotters backend
MMR insertion/times/10000
                        time:   [4.8152 ms 4.8281 ms 4.8422 ms]
Found 1 outliers among 20 measurements (5.00%)
  1 (5.00%) high mild
MMR insertion/times/100000
                        time:   [55.335 ms 55.491 ms 55.668 ms]
Found 1 outliers among 20 measurements (5.00%)
  1 (5.00%) high mild
Benchmarking MMR insertion/times/1000000: Warming up for 3.0000 s
Warning: Unable to complete 20 samples in 5.0s. You may wish to increase target time to 11.8s, or reduce sample count to 10.
MMR insertion/times/1000000
                        time:   [577.75 ms 578.79 ms 580.09 ms]
Found 1 outliers among 20 measurements (5.00%)
  1 (5.00%) high mild

MMR gen proof           time:   [4.9548 µs 4.9666 µs 4.9824 µs]
Found 3 outliers among 20 measurements (15.00%)
  2 (10.00%) high mild
  1 (5.00%) high severe

MMR verify              time:   [3.7701 µs 3.7803 µs 3.7991 µs]
Found 2 outliers among 20 measurements (10.00%)
  1 (5.00%) high mild
  1 (5.00%) high severe

This PR:

     Running benches/helper_benchmark.rs (target/release/deps/helper_benchmark-e2502a0a9f6cdf94)
Gnuplot not found, using plotters backend
left_index_to_pos       time:   [10.093 ns 10.117 ns 10.146 ns]
                        change: [-0.3953% -0.0791% +0.2683%] (p = 0.66 > 0.05)
                        No change in performance detected.
Found 15 outliers among 100 measurements (15.00%)
  3 (3.00%) high mild
  12 (12.00%) high severe

left_index_to_mmr_size  time:   [9.9643 ns 9.9774 ns 9.9937 ns]
                        change: [-1.5135% -1.2727% -1.0323%] (p = 0.00 < 0.05)
                        Performance has improved.
Found 11 outliers among 100 measurements (11.00%)
  1 (1.00%) low mild
  3 (3.00%) high mild
  7 (7.00%) high severe

     Running benches/mmr_benchmark.rs (target/release/deps/mmr_benchmark-f01489cae9dc3cf8)
Gnuplot not found, using plotters backend
MMR insertion/times/10000
                        time:   [4.7629 ms 4.7760 ms 4.7898 ms]
                        change: [-1.4198% -1.0147% -0.6417%] (p = 0.00 < 0.05)
                        Change within noise threshold.
MMR insertion/times/100000
                        time:   [54.792 ms 54.899 ms 55.013 ms]
                        change: [-1.4486% -1.0665% -0.7209%] (p = 0.00 < 0.05)
                        Change within noise threshold.
Benchmarking MMR insertion/times/1000000: Warming up for 3.0000 s
Warning: Unable to complete 20 samples in 5.0s. You may wish to increase target time to 11.6s, or reduce sample count to 10.
MMR insertion/times/1000000
                        time:   [573.59 ms 574.87 ms 576.32 ms]
                        change: [-0.9832% -0.6770% -0.3527%] (p = 0.00 < 0.05)
                        Change within noise threshold.
Found 1 outliers among 20 measurements (5.00%)
  1 (5.00%) high mild

MMR gen proof           time:   [4.8408 µs 4.8519 µs 4.8724 µs]
                        change: [-3.8207% -1.9915% -0.0372%] (p = 0.05 > 0.05)
                        No change in performance detected.
Found 2 outliers among 20 measurements (10.00%)
  1 (5.00%) high mild
  1 (5.00%) high severe

MMR verify              time:   [3.7542 µs 3.7672 µs 3.7917 µs]
                        change: [-2.9870% -0.5610% +1.8429%] (p = 0.67 > 0.05)
                        No change in performance detected.
Found 2 outliers among 20 measurements (10.00%)
  1 (5.00%) high mild
  1 (5.00%) high severe