Make error when submitting command in incorrect context more explicit
Make error when submitting command in incorrect context more explicit

So error message `ERR only (P)SUBSCRIBE / (P)UNSUBSCRIBE / PING / QUIT allowed in this context` will become
`ERR 'get' command submitted, but only (P)SUBSCRIBE / (P)UNSUBSCRIBE / PING / QUIT allowed in this context`

pmem/redis,pmem/redis,pmem/redis,pmem/redis