Accessibility: Themes: Only unlink custom logo on the home page if the theme declares support for that.

To accommodate for the change, the `custom-logo` theme feature now accepts the `unlink-homepage-logo` parameter.

If and when the logo is linked on the home page, the link has the `aria-current` attribute for better accessibility.

Follow-up to [48039], [48283].

Props sabernhardt, audrasjb, johnstonphilip, demetris.
Fixes #37011.

git-svn-id: https://develop.svn.wordpress.org/trunk@48749 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/theme.php

@@ -2472,6 +2472,7 @@ function get_theme_starter_content() {
  * @since 5.3.0 Formalized the existing and already documented `...$args` parameter
  *              by adding it to the function signature.
  * @since 5.5.0 The `core-block-patterns` feature was added and is enabled by default.
+ * @since 5.5.0 The `custom-logo` feature now also accepts 'unlink-homepage-logo'.
  *
  * @global array $_wp_theme_features
  *
@@ -2538,11 +2539,12 @@ function add_theme_support( $feature, ...$args ) {
 				$args = array( 0 => array() );
 			}
 			$defaults = array(
-				'width'       => null,
-				'height'      => null,
-				'flex-width'  => false,
-				'flex-height' => false,
-				'header-text' => '',
+				'width'                => null,
+				'height'               => null,
+				'flex-width'           => false,
+				'flex-height'          => false,
+				'header-text'          => '',
+				'unlink-homepage-logo' => false,
 			);
 			$args[0]  = wp_parse_args( array_intersect_key( $args[0], $defaults ), $defaults );