subrepo: improve help for git subrepo support Add details on which commands are supported for git subrepos.

subrepo: update help for commit to reflect new default behavior Update the subrepo help to be consistent with the new default behavior, which is to abort if any subrepo is dirty.

merge with stable

i18n: disable translations with conflicting prompt keys (issue3082) This is just a stopgap until a proper solution is implemented.

log: hide hidden option until it actually does something

phases: add a very simple test Note that the expected output is wrong as is should be phase-1. But the machinery to plant new root is to come in later commit.

phases: add a phase template keyword