worktree.guessRemote::
	With `add`, if no branch argument, and neither of `-b` nor
	`-B` nor `--detach` are given, the command defaults to
	creating a new branch from HEAD.  If `worktree.guessRemote` is
	set to true, `worktree add` tries to find a remote-tracking
	branch whose name uniquely matches the new branch name.  If
	such a branch exists, it is checked out and set as "upstream"
	for the new branch.  If no such match can be found, it falls
	back to creating a new branch from the current HEAD.