rust-chg: have attach_io() simply take reference of AsRawFd object We no longer have to deal with the restriction of the Future type. Before, these file objects couldn't be references and that's the only reason why we had to make stderr an Option<T>. This fixes future type deduction issue of stderr = None, where rustc would complain that T of Option<T> couldn't be deduced. Differential Revision: https://phab.mercurial-scm.org/D8443

rust-status: check for '.hg' regardless of file type (issue6300) '.hg' would show up in `hg status` if were a symlink. Differential Revision: https://phab.mercurial-scm.org/D8461

rust: remove extra empty line This is a gratuitous cleanup. Differential Revision: https://phab.mercurial-scm.org/D8460

upgrade: properly filter action depending on planned work The `determineactions` function filters out deficiency that are not scheduled to be fixed by the target repository configuration. However it only did so for requirement we currently support, letting other actions for unsupported requirement through even if the target repo configuration did not request it. As a result the output of the command was easily polluted by experimental feature with no upgrade support. We rework the code to still filter out requirement based action without the faulty filtering. Differential Revision: https://phab.mercurial-scm.org/D8427