message: add doc for where default settings go in config file now we're here
diff: @@ -15,7 +15,7 @@ order of prioirty, are:
  * `room-account` - The current user's account, but only when in a specific room
  * `account` - The current user's account
  * `room` - A specific room (setting for all members of the room)
  -* `config` - Values are defined by `config.json`
  +* `config` - Values are defined by the `settingDefaults` key in `config.json`
  * `default` - The hardcoded default for the settings
  Individual settings may control which levels are appropriate for them as part of the defaults. This is often to ensure
  