copies-rust: pre-indent some code to clarify the next patch
The next patch will need this new indentation, having it done explicitly
beforehand makes that next patch clearer.
Differential Revision: https://phab.mercurial-scm.org/D9305
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"phabricator.uri": "https://phab.mercurial-scm.org/",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}