tests: add optional setsockopt() output on Python 3 Tests still don't pass. But this gets us a little closer. Differential Revision: https://phab.mercurial-scm.org/D5699

wireprotov2peer: rewrite character traversal to use slices Otherwise on Python 3 we iterate over integers instead of a bytes instance and the comparison fails. Differential Revision: https://phab.mercurial-scm.org/D5698

wireprotov2server: don't attempt to cast command name I'm not sure why this was added. The command name should already be bytes. Differential Revision: https://phab.mercurial-scm.org/D5697

wireprotov2server: use pycompat.strkwargs when calling cachekeyfn Differential Revision: https://phab.mercurial-scm.org/D5696

diffstat: make --git work properly on renames (issue6025) `$ hg diff --stat --git` shows only the new filename on renames. I added the old filename also to the output to make it identical with the output of `$ git diff --stat`. Differential Revision: https://phab.mercurial-scm.org/D5628

cmdutil: drop obsolete comment about updating to '.' Obsolete since cf68e2649e0a (status: advertise --abort instead of 'update -C .' to abort a merge, 2018-08-09) and 5b04b6204931 (status: advertise --abort instead of 'update -C .' to abort graft, 2018-08-09). Differential Revision: https://phab.mercurial-scm.org/D5694