message: Improve change note message
diff: * Compact now throws an exception if writing fails for some reason
  instead of ignoring errors and possibly causing corruption.
  + In particular, this solves file truncation causing "bad header" exceptions
  + after a compact operation on a file system that is running out of disk space.
  PR [#2852](https://github.com/realm/realm-core/pull/2852).
  ### Breaking changes
  