Fix docblock for validate_receiver_email

includes/gateways/paypal/includes/class-wc-gateway-paypal-ipn-handler.php

@@ -147,7 +147,8 @@ class WC_Gateway_Paypal_IPN_Handler extends WC_Gateway_Paypal_Response {
 	}
 
 	/**
-	 * Check payment amount from IPN matches the order
+	 * Check receiver email from PayPal. If the receiver email in the IPN is different than what is stored in
+	 * WooCommerce -> Settings -> Checkout -> PayPal, it will log an error about it
 	 * @param  WC_Order $order
 	 */
 	protected function validate_receiver_email( $order, $receiver_email ) {