style: use core `ready`, `poll_fn`, and `pin!` #925

Job	Run time
just check	4m 53s
docs	2m 34s
netlify_dryrun	2m 50s
just clippy	4m 58s
rustfmt	24s
just test	2m 14s
cargo miri test --package forth3 (host)	1m 27s
cargo build mnemos-d1	1m 28s
cargo build mnemos-esp32c3-buddy	1m 5s
cargo build mnemos-x86_64-bootloader	2m 20s
all systems go!	1s
	24m 14s

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