Docs: Add missing `@since` tag for `WP_Recovery_Mode_Cookie_Service::parse_cookie()`.

Props mukesh27.
Fixes #46993.

git-svn-id: https://develop.svn.wordpress.org/trunk@45253 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/class-wp-recovery-mode-cookie-service.php

@@ -139,6 +139,8 @@ final class WP_Recovery_Mode_Cookie_Service {
 	/**
 	 * Parses the cookie into its four parts.
 	 *
+	 * @since 5.2.0
+	 *
 	 * @param string $cookie Cookie content.
 	 * @return array|WP_Error Cookie parts array, or error object on failure.
 	 */