Encryption topic needs editing

[tbedford]

The encryption topic, for both realtime and REST interfaces, needs editing for clarity. For example:

Clients that do not specify a key will be delivered the still-encrypted message payloads that they may then still wish to decrypt offline.

Encryption pages can be found here:

• Encryption - Realtime
• Encrytpion - REST

┆Issue is synchronized with this Jira Task by Unito