Insufficient description about Will Payload in the mqtt 5.0 documentation

[hiback]

In the Will Message section of the MQTT 3.1.1 documentation, a two-byte length prefix is mentioned before the actual message.

However, this is not mentioned in the Will Payload section of the MQTT 5.0 documentation.

Do we still need this in MQTT 5.0?
If so, should we add that description for better clarity?