Make book child content-type configurable per enabled book content-type

This extension is being deprecated, see 🌱 [Meta] Tasks to deprecate Book module Active . It will be removed from core and moved to a contrib project, 📌 [11.x] [Meta] Tasks to remove Book Active .

This is now Postponed. The status is set according to two policies. The Remove a core extension and move it to a contributed project → and the Extensions approved for removal → policies.

This issue may be re-opened if it can be considered critical → , If unsure, re-open the issue and ask in a comment.

Oof, i feel issues should not be postponed/closed until they can be moved along with the core extension when it is moved to a contrib module.

Really, all core Drupal modules should be brought in by composer, so there is not this traumatic phase while a module is being moved to contrib (or from contrib). It should be easy to fork — or branch — a core module same as a contrib one (keep development in the same namespace but swappable).

Anyhow this patch works (you may get errors trying to print Add child page links until you save the new configuration for the first time) and i hope contributors here will put in to be maintainers of the book-in-contrib to be! (Also on that, #1261130 is a very interesting direction.)

Patch for Drupal 10.2.x but doesn't use the Config Target API that was recently changed.

Missed a file

Patch for Drupal 10.2.x but doesn't use the Config Target API that was recently changed.