copy: add option to unmark file as copied To unmark a file as copied, the user currently has to do this: hg forget <dest> hg add <dest> The new command simplifies that to: hg copy --forget <dest> That's not a very big improvement, but I'm planning to also teach `hg copy [--forget]` a `--at-rev` argument for marking/unmarking copies after commit (usually with `--at-rev .`). Differential Revision: https://phab.mercurial-scm.org/D8029