Themes: Add an ID to the block theme skip link.

Add the ID `wp-skip-link` to the block theme generated skip link, so that block themes have a standardized target at the top of the `body` element.

Props philliproth, audrasjb, debarghyabanerjee, sabernhardt, joedolson, apermo.
Fixes #62311.

git-svn-id: https://develop.svn.wordpress.org/trunk@59559 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/theme-templates.php

@@ -203,6 +203,7 @@ function wp_enqueue_block_template_skip_link() {
 		// Create the skip link.
 		skipLink = document.createElement( 'a' );
 		skipLink.classList.add( 'skip-link', 'screen-reader-text' );
+		skipLink.id = 'wp-skip-link';
 		skipLink.href = '#' + skipLinkTargetID;
 		skipLink.innerHTML = '<?php /* translators: Hidden accessibility text. */ esc_html_e( 'Skip to content' ); ?>';