Remove remaining cruft from "git checkout --to", which
transitioned to "git worktree add".
* es/worktree-add:
config: rename "gc.pruneWorktreesExpire" to "gc.worktreePruneExpire"
Documentation/git-worktree: wordsmith worktree-related manpages
Documentation/config: fix stale "git prune --worktree" reference
Documentation/git-worktree: fix incorrect reference to file "locked"
Documentation/git-worktree: consistently use term "linked working tree"