Merge branch 'master' of github.com:/reasonml/reason

* 'master' of github.com:/reasonml/reason:
  add changelog entry for #2721
  recognize `mel.obj` instead of `bs.obj` (#2721)
  prepare to release 3.9
  parser: fully qualify most modules (#2719)
  run dune build @fmt
  rename history -> changes
  chore: prepare 3.9.0 (#2718)