Document new automation triggers that will be released in 3.3

https://github.com/nightscout/AndroidAPS/pull/3267

These automation triggers were added to dev. However these and other time usage based triggers have the limitation that equals cannot be used. We should document this and suggest a correct way to use it, see:
https://discord.com/channels/629952586895851530/1076120802476441641/1247277529417650187