zk-token-sdk: Fix incorrect mention of OsRng in docs #2835

Job	Run time
cargo-test-sbf (token/program)	16m 43s
cargo-test-sbf (instruction-padding/program, token/program-2022, token/program-2022-test)	23m 3s
check	0s
cargo-test-sbf (associated-token-account/program, associated-token-account/program-test)	17m 1s
test	0s
cargo-test-sbf (token-upgrade/program)	19m 30s
cargo-test-sbf (feature-proposal/program)	14m 53s
cargo-test-sbf (governance/addin-mock/program, governance/program)	21m 59s
cargo-test-sbf (memo/program)	17m 11s
cargo-test-sbf (name-service/program)	14m 55s
cargo-test-sbf (stake-pool/program)	19m 36s
cargo-test-sbf (single-pool/program)	18m 5s
	3h 2m 56s

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