Formatting: Make sure `links_add_target()` adds the `target` attribute to the correct tag.

Previously, the attribute could unintentionally be added to a tag that starts with the same characters, e.g. `<aside>` instead of `<a>`.

Props antonlukin.
Fixes #51313.
Built from https://develop.svn.wordpress.org/trunk@48983


git-svn-id: http://core.svn.wordpress.org/trunk@48745 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/formatting.php

@@ -5243,7 +5243,7 @@ function links_add_target( $content, $target = '_blank', $tags = array( 'a' ) )
 	global $_links_add_target;
 	$_links_add_target = $target;
 	$tags              = implode( '|', (array) $tags );
-	return preg_replace_callback( "!<($tags)([^>]*)>!i", '_links_add_target', $content );
+	return preg_replace_callback( "!<($tags)((\s[^>]*)?)>!i", '_links_add_target', $content );
 }
 
 /**

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.6-alpha-48982';
+$wp_version = '5.6-alpha-48983';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.