evolve: retain extras when relocating a commit Building on 2cd959fe631a::82e5a9b1ef1e (submitted as https://foss.heptapod.net/mercurial/mercurial-devel/-/merge_requests/511) and cbcbf63b6dbf, this change addresses the regression introduced in b1d1f4ade142::53d63b608230 (from !458) when evolve stopped including extras added by downstream plugins when relocating commits for evolve. Mercurial now provides an extension point at mercurial.rewriteutil.preserve_extras_on_rebase; it's a list of extras to be retained, that Evolve uses, and that downstream users might extend.