Template:Shelf:Page/Update ancestry/doc

This template handles the case that an ancestry page must be updated, for Shelf:Page/Check ancestry2.

Usage
Two parameter are required.
 * &mdash; the name of the shelf, without the  prefix.
 * &mdash; wikilisp-formatted proposed list of ancestors for.
 * &mdash; wikilisp-formatted current list of ancestors for.

Internals
Atm, the intended value of the ancestry is simply provided for copy-paste. A dialog-based assistant could insert it directly, without requiring the value to pass through the user's hands.