tests/test-revert-unknown.t

cmdserver: document message-encodings and channel output options

While writing the previous patch, I noticed these options are undocumented.
In my testing, a separate status/error message channel works well in GUI
frontend as we no longer have to sort out data and message from mixed outputs.
So let's mark it as not experimental.

  $ hg init
  $ touch unknown

  $ touch a
  $ hg add a
  $ hg ci -m "1"

  $ touch b
  $ hg add b
  $ hg ci -m "2"

Should show unknown

  $ hg status
  ? unknown
  $ hg revert -r 0 --all
  removing b

Should show unknown and b removed

  $ hg status
  R b
  ? unknown

Should show a and unknown

  $ ls -A
  .hg
  a
  unknown