chore: update Rust to `nightly-2024-01-20` #843

Job	Run time
docs	1m 0s
docs	1m 9s
netlify_dryrun	59s
netlify_dryrun	1m 0s
just check	35s
just check	3m 48s
just clippy	1m 54s
just clippy	1m 2s
rustfmt	18s
rustfmt	18s
just test	0s
just test	2m 13s
cargo miri test (host)	0s
cargo miri test (host)	1m 8s
cargo build ${{ matrix.package }}	0s
cargo build mnemos-d1	1m 35s
cargo build mnemos-esp32c3-buddy	59s
cargo build mnemos-x86_64-bootloader	2m 8s
	20m 6s

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