unshelve: delete shelvedstate after a successful unshelve --continue `unshelve --continue` was preventing the deletion of `shelvedstate` on a partial `unshelve`. Ideally, `shelvedstate` should be deleted after a successful `unshelve`. Now, the behavior of `unshelve --continue` will be as follows in interactive mode: 1] The user tried to `unshelve` changes interactively but, ran into conflicts. 2] They resolved the conflicts and triggered `unshelve --continue` but, unshelved changes partially. 3] Now, on trying to do `unshelve --continue` again will abort as the last `unshelve` was successful and we are deleting the `shelvedstate`. 4] If they want to unshelve the remaining shelved change, they need to trigger `unshelve` without `--continue`. Differential Revision: https://phab.mercurial-scm.org/D6694

unshelve: handle stripping changesets on interactive mode On interactive mode, changesets on `nodestoremove` should be stripped regardless of the shelve is partial or not. This patch modifies `unshelvecontinue()` to do that. Differential Revision: https://phab.mercurial-scm.org/D6686

byteify-strings: add --version argument This is indispensable for automated tools to detect changes in behavior.

byteify-strings: add space in special comments to silence flake8 error This is done soon enough that nobody has had the time to use this feature yet.

revset: drop argument when it's None getstack's definition is `getstack(repo, rev=None)`, so providing None explicitly is unnecessary. Moreover, when x is not None, it's definitely not a revision but a part of a parsed tree of revset arguments. Differential Revision: https://phab.mercurial-scm.org/D6707

stack: remove unnecessary reverse() predicate Stack already sorts revisions, so no need to do it twice. This change was a part of D2400, which didn't land for other reasons. See also D2399, where this change was suggested. Differential Revision: https://phab.mercurial-scm.org/D6706

automation: increase root volume size on Linux It is close to full in the AMI. I actually ran out of space running tests without increasing the volume size! Differential Revision: https://phab.mercurial-scm.org/D6716

automation: install Rust in Linux environment This will install Rust 1.31.1, 1.34.2, and whatever stable is at the time the install runs. We install 1.31.1 as our minimum supported Rust version (I think that's what we're currently targeting) and 1.34 because that's what Debian 10 is shipping. Differential Revision: https://phab.mercurial-scm.org/D6715

automation: update packages in requirements files We like keeping up to date. The content of the autogenerated files changed slightly because I used a newer version of `pip-compile` than what was used previously. Differential Revision: https://phab.mercurial-scm.org/D6714

automation: install latest Python versions This required bumping the pyenv commit so the new versions are available. Differential Revision: https://phab.mercurial-scm.org/D6713