evolve: retain extras when relocating a commit
This MR is !499 (closed) but without the test changes.
From the main commit:
Building on mercurial-devel!511 (merged), this change addresses the regression introduced in !458 (merged) when evolve stopped including extras added by downstream plugins when relocating commits for evolve. Evolve now provides an extension point (evolvecmd.retain_extras function) where downstream users might extend the list of extras to be retained.
Edited by Jason R. Coombs