`org-node--make-regexp-for-time-format' check issue

in `org-node--make-regexp-for-time-format`, there's a check ``` elisp (when (string-match-p "[[:alnum:]]" (substring format 0 -1)) (error "Cannot safely rename if `org-node-file-timestamp-format' does not end in a separator such as a dash")) ``` shouldn't `(substring format 0 -1)` here be instead `(substring format -1)` ? Because currently it is ignoring the final character of `org-node-file-timestamp-format` and just checking if everything before it is alphanumeric (and so complaining about an `org-node-file-timestamp-format` value of `"%Y%m%d%H%M%S-"`, which I think should be okay).