Issue #2246661 by ivanjaros: Some templates are missing 'Default theme...

Issue #2246661 by ivanjaros: Some templates are missing 'Default theme implementation ..' statement.

core/modules/book/templates/book-tree.html.twig

 {#
 /**
  * @file
+ * Default theme implementation for a book tree.
+ *
  * Returns HTML for a wrapper for a book sub-tree.
  *
  * Available variables:

core/modules/filter/templates/filter-caption.html.twig

 {#
 /**
+ * @file
+ * Default theme implementation for a filter caption.
+ *
  * Returns HTML for a captioned image, audio, video or other tag.
  *
  * Available variables

core/modules/node/templates/node-edit-form.html.twig

 {#
 /**
  * @file
+ * Default theme implementation for a node edit form.
+ *
  * Two column template for the node add/edit form.
  *
  * This template will be used when a node edit form specifies 'node_edit_form'