uncommit: enable support for adding a note This comes from the evolve extension's version of uncommit. The logic was already in place, and appears to be the last of the trivial things that can be enabled. Should these note options (including on amend) be marked advanced to keep the help text clutter level down? Differential Revision: https://phab.mercurial-scm.org/D6857

amend: enable support for using the secret phase This comes from the evolve extension's version of amend. The logic was already in place, and appears to be the last of the trivial things that can be enabled. Differential Revision: https://phab.mercurial-scm.org/D6856

amend: enable support for closing the branch This comes from the evolve extension's version of amend. The logic was already in place. Differential Revision: https://phab.mercurial-scm.org/D6855

amend: prevent '\n' in the note string This comes from the evolve function. I'm not sure why this check was missing in core, since it was present when the length check was added to evolve. I didn't flag this as BC because 530b7361e3a9 mentioned this argument wasn't added to the release notes due to no display capability, and that hasn't changed AFAIK. Differential Revision: https://phab.mercurial-scm.org/D6854

amend: add option to update to the current user This is also from the evolve extension's version of amend. A side effect of this refactoring is for uncommit to support `rewrite.update-timestamp`. Differential Revision: https://phab.mercurial-scm.org/D6853

bundle2: fix an off-by-one in debug message of number of parts Differential Revision: https://phab.mercurial-scm.org/D6850