update WPCS to v3 and apply minor code style tweaks

[stklcode]

• use printf() instead of echo sprintf()
• remove parentheses around require_once
• fix precision alignment, equals signs and double arrows
• rename $class parameter of autoload function to $class_name
• use wp_parse_url() instead of parse_url()
• update WPCS definitions to v3.0 (runs with PHP 8.2)