Add docs to the token interface #3906

Job	Run time
fmt	16s
cargo-deny (advisories)	39s
cargo-deny (bans licenses sources)	36s
build-fuzz	33s
build-and-test (msrv, ubuntu-latest, x86_64-unknown-linux-gnu)	7m 35s
check-git-rev-deps	14s
build-and-test (msrv, ubuntu-latest, aarch64-unknown-linux-gnu, true)	2m 12s
build-and-test (msrv, macos-latest, x86_64-apple-darwin)	14m 9s
docs	2m 6s
readme	30s
build-and-test (msrv, macos-latest, aarch64-apple-darwin)	8m 49s
rust-analyzer-compat	2m 23s
build-and-test (msrv, windows-latest, x86_64-pc-windows-msvc)	13m 21s
semver-checks	4m 3s
build-and-test (latest, ubuntu-latest, x86_64-unknown-linux-gnu)	8m 38s
build-and-test (latest, ubuntu-latest, aarch64-unknown-linux-gnu, true)	2m 8s
build-and-test (latest, macos-latest, x86_64-apple-darwin)	25m 0s
build-and-test (latest, macos-latest, aarch64-apple-darwin)	12m 1s
publish-dry-run	0s
build-and-test (latest, windows-latest, x86_64-pc-windows-msvc)	12m 57s
complete	1s
	1h 58m 11s

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