merge: don't check for unknown files in IMM Differential Revision: https://phab.mercurial-scm.org/D1214

rebase: enable multidest by default This was intended to be done by D470. But there was a minor documentation issue. The feature is quite usable now so it gets formally documented and enabled. There is no behavior change for people not using the `SRC` or `ALLSRC` in rebase destination revset. .. feature:: Rebase with different destination per source revision Previously, rebase only supports one unique destination. Now ``SRC`` and ``ALLSRC`` can be used in rebase destination revset to precisely define destination per each individual source revision. For example, the following command could move some orphaned changesets to reasonable new places so they become no longer orphaned:: hg rebase -r 'orphan()-obsolete()' -d 'max((successors(max(roots(ALLSRC) & ::SRC)^)-obsolete())::)' Differential Revision: https://phab.mercurial-scm.org/D1063

overlayworkingctx: make clean() public It will be called directly by rebase after concluding a node. Differential Revision: https://phab.mercurial-scm.org/D1230