OptionalerrorA human-readable reason the requested shortcode was rejected, or
undefined when the requested value was accepted. When set, the caller
should surface this message and fall back to shortcode.
The shortcode to persist. The requested value when it is valid and unique; otherwise the entry's existing shortcode (the edit is kept, only the shortcode change is refused).
The decision produced by planBodyShortcode: the shortcode a body part or body location should be saved with, and — when the requested value was rejected — why.