General: Use correct escaping function for form `action` attributes.

Props chintan1896, audrasjb.
Fixes #53150.
Built from https://develop.svn.wordpress.org/trunk@50809


git-svn-id: http://core.svn.wordpress.org/trunk@50418 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/includes/post.php

@@ -2258,7 +2258,7 @@ function the_block_editor_meta_boxes() {
 	<form class="metabox-base-form">
 	<?php the_block_editor_meta_box_post_form_hidden_fields( $post ); ?>
 	</form>
-	<form id="toggle-custom-fields-form" method="post" action="<?php echo esc_attr( admin_url( 'post.php' ) ); ?>">
+	<form id="toggle-custom-fields-form" method="post" action="<?php echo esc_url( admin_url( 'post.php' ) ); ?>">
 		<?php wp_nonce_field( 'toggle-custom-fields', 'toggle-custom-fields-nonce' ); ?>
 		<input type="hidden" name="action" value="toggle-custom-fields" />
 	</form>

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.8-alpha-50808';
+$wp_version = '5.8-alpha-50809';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.