* [fix] Clarified docstatus transition exceptions
Exceptions issued by the document.py `check_docstatus_transition` method are potentially very misleading. In cases where an invalid docstatus is used, users receive an confusing exception stating "Cannot change docstatus from 0 to 2" or "Cannot change docstatus from 1 to 0".
This PR adds an additional exception message when an invalid docstatus is used.
* fix: Clarified docstatus transition exceptions
Added additional clarifications to exception messages