phabricator: add commenting to phabsend for new/updated Diffs Especially useful when sending updates to existing Revisions so one can specify the sort of changes e.g. "Address review comments" or "Rebase to tip" If the diff content hasn't changed then it only needs a metadata update which doesn't show in the Phabricator updates UI, so don't add a comment that will. Differential Revision: https://phab.mercurial-scm.org/D6496

py3: fix test-bookmarks-corner-case.t For some reasons, the output of print was not going through. Replaced that ui.status(). Differential Revision: https://phab.mercurial-scm.org/D6481

py3: fix test-fix-metadata.t # skip-blame as just b'' prefixes Differential Revision: https://phab.mercurial-scm.org/D6480

py3: add b'' prefix at one place in run-tests.py #skip-blame because just b'' prefix Differential Revision: https://phab.mercurial-scm.org/D6482

copies: separate added/removed files by newline instead of null This makes it more consistent with how we encode copies (newline-separated lists of null-separated pairs). This perhaps makes {extras} a little less readable (?) despite avoiding the escaping. I don't know how I feel about this patch. I'm okay with it being queued or dropped. Differential Revision: https://phab.mercurial-scm.org/D6486

copies: also encode p[12]copies destination as index into "files" list This is mostly for consistency with the filesaddes/filesremoved fields, but it should also save a bit of space. Differential Revision: https://phab.mercurial-scm.org/D6431