message: Document fixed datagram servant registration
diff: @@ -176,6 +176,13 @@ is based on [Keep a Changelog](https://keepachangelog.com).
  assume that the parsed URI for `tcp://127.0.0.1:8080` returns an IP address
  when calling `authority().host`.
  +## [0.17.7] - Unreleased
  +
  +### Fixed
  +
  +- Datagram servants are not added to their broker on creation and should no
  + longer prevent system shutdown if they never enconutered a new endpoint.
  +
  ## [0.17.6] - 2020-07-24
  ### Fixed
  