[PATCH 1 of 3] copies: extract an explicit `computechangesetcopie` method from context

[Yuya Nishihara]

On Tue, 06 Aug 2019 11:50:38 +0200, Pierre-Yves David wrote:
> # HG changeset patch
> # User Pierre-Yves David <pierre-yves.david at octobus.net>
> # Date 1565054260 -7200
> #      Tue Aug 06 03:17:40 2019 +0200
> # Node ID fc8e461200c7262246ebd610100bcf9a75ded461
> # Parent  f95b59ffc307c4549d9640a81d750a99bd75f423
> # EXP-Topic extrameta
> # Available At https://bitbucket.org/octobus/mercurial-devel/
> #              hg pull https://bitbucket.org/octobus/mercurial-devel/ -r fc8e461200c7
> copies: extract an explicit `computechangesetcopie` method from context

The idea seems fine, but the last two functions are unrelated to "copies",
and I feel the copies module is more like a set of copy-detection algorithms.

Maybe it's better to move to scmutil or new module.