Automatically add backlinks when copying templates

Experimental

Backlinks are an integral part of the checklist for the item at point, so why
not include them per default?

Copying is for now done unconditionally and without any customization.  If those
will turn out necessary, then they will be added later.

site-lisp/db-org.el

@@ -870,6 +870,11 @@ otherwise."
     (unless template-pom
       (user-error "Cannot find template via TEMPLATE_ID property or top-most sibling"))
 
+    (insert "\nBacklinks (not DONE, all parents, no archives):\n\n")
+    (org-dblock-write:db/org-backlinks '(:org-ql-match (not (done))
+                                         :parent-depth nil
+                                         :archive nil))
+    (insert "\n\nTemplate:\n")
     (db/org-copy-body-from-item-to-point template-pom)))
 
 (defun db/org-copy-body-from-item-to-point (pom)