tests/test-update-renames.t

obsolete: refactor writemarkers to only encode them

The function is now able to write the version header as necessary. The function
now yield bytes to be written to a stream.

This should ease later use of this function for wireprotocol based exchanged.

Prepare the public use of the writemarker by wireprotocol function.

Test update logic when there are renames

Update with local changes across a file rename

  $ hg init

  $ echo a > a
  $ hg add a
  $ hg ci -m a

  $ hg mv a b
  $ hg ci -m rename

  $ echo b > b
  $ hg ci -m change

  $ hg up -q 0

  $ echo c > a

  $ hg up
  merging a and b to b
  warning: conflicts during merge.
  merging b incomplete! (edit conflicts, then use 'hg resolve --mark')
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges
  [1]