Docs: Document that allowed_tags() is no longer used in core as of WordPress 4.4.

Previously, it was used in core and older bundled themes to display the list of allowed tags in the comment form.

Follow-up to [709], [2009], [2012], [2032], [2040], [13030], [14365], [32858], [34316], [34351].

See #55646.

git-svn-id: https://develop.svn.wordpress.org/trunk@53703 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/general-template.php

@@ -2462,6 +2462,7 @@ function delete_get_calendar_cache() {
  * attributes are supported. As well as any plugins which want to display it.
  *
  * @since 1.0.1
+ * @since 4.4.0 No longer used in core.
  *
  * @global array $allowedtags
  *