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