Wordpress - Adding revision support to WooCommerce product content

As you pointed out already there is a filter.

add_filter( 'woocommerce_register_post_type_product', 'wpse_modify_product_post_type' );

function wpse_modify_product_post_type( $args ) {
     $args['supports'][] = 'revisions';

     return $args;
}

Put that in your child theme's functions.php file.