phab-refresh: use a special comment on the stable branch Phabricator make it hard to spot the branch information. As a result patch intended for stable are consistently queued for default. We add a special command and flashy GIF to try to attract reviewer attention on the fact patch are intended for stable. Differential Revision: https://phab.mercurial-scm.org/D10464

phab-refresh: extract the comment in a variable This make the script more readable and it is about to become more complex. Differential Revision: https://phab.mercurial-scm.org/D10463

tests: make test-archive.t pass on py3.9 (issue6504) Something got stricter at parsing URL query parameters and now the parameters need to be separated by "&"; ";" is no longer allowed. See issue6504 for details. Differential Revision: https://phab.mercurial-scm.org/D10472

errors: raise RemoteError in some places in exchange.py This is part of https://www.mercurial-scm.org/wiki/ErrorCategoriesPlan Differential Revision: https://phab.mercurial-scm.org/D10467

errors: introduce a class for remote errors Having an exception for remote errors makes it much easier to exit with the right detailed exit code. Differential Revision: https://phab.mercurial-scm.org/D10466

errors: make OutOfBandError extend Abort I'm about to create a new `RemoteError` exception and make `OutOfBandError` extend it. This patch prepares for that. Differential Revision: https://phab.mercurial-scm.org/D10465