graft: add a new `--stop` flag to stop interrupted graft This patch adds a new flag `--stop` to `hg graft` command which stops the interrupted graft. The `--stop` flag takes back you to the last successful step i.e. it will keep your grafted commits, it will just clear the mergestate and interrupted graft state. The `--stop` is different from `--abort` flag as the latter also undoes all the work done till now which is sometimes not what the user wants. Suppose you grafted a lot of changesets, you encountered conflicts, you resolved them, did `hg graft --continue`, again encountered conflicts, continue, again encountered conflicts. Now you are tired of solving merge conflicts and want to resume this sometimes later. If you use the `--abort` functionality, it will strip your already grafted changesets, making you loose the work you have done resolving merge conflicts. A general goal related to this flag is to add this flag to `rebase` and `histedit` too. The evolve command already has this --stop flag. Tests are added for the new flag. .. feature:: `hg graft` now has a `--stop` flag to stop interrupted graft. Differential Revision: https://phab.mercurial-scm.org/D3668