tests/test-nested-repo.t

merge: make 'diverging renames' diagnostic a more helpful note.

See the Hg Book on why we actually want to detect this case:
http://hgbook.red-bean.com/read/mercurial-in-daily-use.html#id364290

Before:

$ hg up deadbeef
warning: detected divergent renames of X to:
...

After:

$ hg up deadbeef
note: possible conflict - X was renamed multiple times to:
...

No functionality change.

  $ hg init a
  $ cd a
  $ hg init b
  $ echo x > b/x

Should print nothing:

  $ hg add b
  $ hg st

Should fail:

  $ hg st b/x
  abort: path 'b/x' is inside repo 'b'
  [255]
  $ hg add b/x
  abort: path 'b/x' is inside repo 'b'
  [255]

Should fail:

  $ hg add b b/x
  abort: path 'b/x' is inside repo 'b'
  [255]
  $ hg st

Should arguably print nothing:

  $ hg st b

  $ echo a > a
  $ hg ci -Ama a

Should fail:

  $ hg mv a b
  abort: path 'b/a' is inside repo 'b'
  [255]
  $ hg st