hghave: move from requiring the PYTHON3 env var to looking for `python3` We're starting to write new utility scripts in Python 3, and I think it's reasonable to expect `python3` to be something we should use if it's present. I wrote the regex to specifically ban Python 3 prior to Python 3.5 because we won't ever support that. I moved the only test that was using $PYTHON3 to just using `python3` directly. Differential Revision: https://phab.mercurial-scm.org/D4290

rename: return error status if any rename/copy failed Ever since 447ea621e50e (copy: propagate errors properly, 2007-12-06), we have returned an error status if the source file did not exist. That commit did not return error status for any other errors, and it's unclear if that was on purpose or not. It seems to me like we should return an error in the other cases to, so that's what this patch does. Differential Revision: https://phab.mercurial-scm.org/D4419

rename: emit hint about using --after consistently Both the code and the message for the case where the source file was missing was inconsistent with the other similar messages. Differential Revision: https://phab.mercurial-scm.org/D4418

rename: quote hg commands in warnings I think we usally use single quotes around hg commands in messages. Differential Revision: https://phab.mercurial-scm.org/D4417

zsh_completion: complete hg files Differential Revision: https://phab.mercurial-scm.org/D4361

zsh_completion: adjust usage of common options addremove, remove and serve accept -S/--subrepos, and purge actually doesn't. qnew accepts -I/--include and -X/--exclude. qrefresh accepts -D/--currentdate, -U/--currentuser, -d/--date and -u/--user. rebase accepts -n/--dry-run. Differential Revision: https://phab.mercurial-scm.org/D4360