pyoxidizer: default to a meaningless release instead of hardcoding 5.8 This way we don't advertise the wrong version, or if we do it's really obvious. To be honest, I'm not even sure that `VERSION` should be optional, but I also have never used the packaging tools so far, this is simply something I saw. Differential Revision: https://phab.mercurial-scm.org/D11360

copy: recommend `--at-rev .` if target was added in parent commit If the target file was added in the working copy parent, it's much more likely that the user meant to use `--at-rev .` (to record the copy/rename in the that commit) than `--force` (to replace the just-added file by another file). Differential Revision: https://phab.mercurial-scm.org/D11667

fix: appease pyflakes and make unused variables more obvious pyflakes is complaining that `baserevs` is redefined by the list comprehension, and while this lint can be valuable, it's not actually a problem here. Differential Revision: https://phab.mercurial-scm.org/D11683