chore: apply `unreachable_pub` lint to crates #632

Job	Run time
minimal-versions / minimal-versions	35s
set-msrv / set-msrv	5s
test (stable)	28s
test (1.85.0)	1s
build (1.85.0, thumbv7em-none-eabi)	1m 36s
build (1.85.0, wasm32-unknown-unknown)	1s
build (stable, wasm32-unknown-unknown)	1m 37s
build (stable, thumbv7em-none-eabi)	1s
	4m 24s

Provide feedback