Themes: Re-order valid link pseudo classes.

Re-order the link pseudo classes to follow the long term LoVe (F)HA rule when set via `theme.json`.

In order that the CSS cascade behaves in a predictable manner, it's recommended that the selectors follow the order `:visited`, `:focus`/`:hover`, `:active`. As order affects the specificity, this ensures the interaction states override the visited states. CSS specificity is really quite beautiful, although complex.

Props mikachan, sabernhardt, davidbaumwald, mukesh27, Mamaduka, desrosj.
Fixes #56928.

Built from https://develop.svn.wordpress.org/trunk@54774


git-svn-id: http://core.svn.wordpress.org/trunk@54326 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/class-wp-theme-json.php

@@ -394,13 +394,18 @@ class WP_Theme_JSON {
 	/**
 	 * Defines which pseudo selectors are enabled for which elements.
 	 *
+	 * The order of the selectors should be: visited, hover, focus, active.
+	 * This is to ensure that 'visited' has the lowest specificity
+	 * and the other selectors can always overwrite it.
+	 *
+	 * See https://core.trac.wordpress.org/ticket/56928.
 	 * Note: this will affect both top-level and block-level elements.
 	 *
 	 * @since 6.1.0
 	 */
 	const VALID_ELEMENT_PSEUDO_SELECTORS = array(
-		'link'   => array( ':hover', ':focus', ':active', ':visited' ),
-		'button' => array( ':hover', ':focus', ':active', ':visited' ),
+		'link'   => array( ':visited', ':hover', ':focus', ':active' ),
+		'button' => array( ':visited', ':hover', ':focus', ':active' ),
 	);
 
 	/**

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.2-alpha-54771';
+$wp_version = '6.2-alpha-54774';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.