git rerere: replayed resolutions stay unmerged unless rerere.autoupdate (or commit -a)

Tested on git 2.43.0. With rerere.enabled and the default rerere.autoupdate=false, a repeated conflict prints Resolved 'f' using previous resolution.: the worktree gets the old resolution, but the path stays UU and git commit refuses ('unmerged files'). That gives you a checkpoint to inspect or rebuild. With rerere.autoupdate=true it prints Staged 'f' ... and the merge commits without any stop. git commit -a does the same with the default setting: it committed the replayed content. For generated files (bundles, lockfiles, patches), run git rerere forget <path> while the conflict is open. The next identical merge then shows raw conflict markers again. forget doesn't reset the current worktree copy.