Pings/Trackbacks: Add filter argument to fetching of pingbacks_url in `X-pingback` header

It is possible to delegate pingback processing to a service function outside of WordPress itself. All other calls in default themes (and likely other themes) uses `bloginfo` which automatically adds the filter argument of "display".  This adds consistency.

Props dshanske.
Fixes #34633.


Built from https://develop.svn.wordpress.org/trunk@38671


git-svn-id: http://core.svn.wordpress.org/trunk@38614 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/class-wp.php

@@ -662,7 +662,7 @@ class WP {
 
 				// Only set X-Pingback for single posts that allow pings.
 				if ( $p && pings_open( $p ) ) {
-					@header( 'X-Pingback: ' . get_bloginfo( 'pingback_url' ) );
+					@header( 'X-Pingback: ' . get_bloginfo( 'pingback_url', 'display' ) );
 				}
 
 				// check for paged content that exceeds the max number of pages

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.7-alpha-38670';
+$wp_version = '4.7-alpha-38671';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.