Document the default list of allowed protocols in the doc block for `wp_allowed_protocols()` and cross-reference in `esc_url()` and the `kses_allowed_protocols` filter.

Props GunGeekATX.
Fixes #32421.


git-svn-id: https://develop.svn.wordpress.org/trunk@32797 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/formatting.php

@@ -3126,9 +3126,7 @@ function esc_sql( $data ) {
  *
  * @param string $url       The URL to be cleaned.
  * @param array  $protocols Optional. An array of acceptable protocols.
- *		                    Defaults to 'http', 'https', 'ftp', 'ftps', 'mailto',
- *                          'news', 'irc', 'gopher', 'nntp', 'feed', 'telnet', 'mms',
- *                          'rtsp', 'svn' if not set.
+ *		                    Defaults to return value of wp_allowed_protocols()
  * @param string $_context  Private. Use esc_url_raw() for database usage.
  * @return string The cleaned $url after the 'clean_url' filter is applied.
  */

src/wp-includes/functions.php

@@ -4506,6 +4506,7 @@ function send_frame_options_header() {
  * @staticvar array $protocols
  *
  * @return array Array of allowed protocols.
+ *               Defaults to 'http', 'https', 'ftp', 'ftps', 'mailto', 'news', 'irc', 'gopher', 'nntp', 'feed', 'telnet', 'mms', 'rtsp', 'svn', 'tel', 'fax', 'xmpp', 'webcal'
  */
 function wp_allowed_protocols() {
 	static $protocols = array();