TDB (RESP): proofread the pubsub commands

[xuniq]

Epic: #4257
Product: Tarantool DB (Redis)
Source: TBD (not implemented yet)
Root document: TBD
SME: @ AlgebraicWolf @ Galiev-Ruslan @ LeonidVas

[xuniq]

Done in https://github.com/tarantool/tdb-redis/pull/165 and https://github.com/tarantool/tdb-redis/pull/166