How to Hide the "Sticky Anchor Fixer" Admin Menu

function plt_hide_sticky_header_anchor_fixer_menus() {
	//Hide the "Settings → Sticky Anchor Fixer" menu.
	remove_submenu_page('options-general.php', 'shaf-settings');
}

add_action('admin_menu', 'plt_hide_sticky_header_anchor_fixer_menus', 11);

Where do I put this code?