bluetooth: Explain why standard names aren't recognized in error message.

LayoutTests/bluetooth/getPrimaryService.html

Index: LayoutTests/bluetooth/getPrimaryService.html
diff --git a/LayoutTests/bluetooth/getPrimaryService.html b/LayoutTests/bluetooth/getPrimaryService.html
index 811b73eb6954f4db344fe73ab3579f9d3b434824..870ea7c8e2bb81c18c594fd7622716fd31dc907d 100644
--- a/LayoutTests/bluetooth/getPrimaryService.html
+++ b/LayoutTests/bluetooth/getPrimaryService.html
@@ -88,7 +88,13 @@ promise_test(() => {
           name: 'SyntaxError',
           message: 'Failed to execute \'getPrimaryService\' on ' +
                    '\'BluetoothGATTRemoteServer\': Invalid Service name: ' +
-                   '\'wrong_name\'.'
+                   '\'wrong_name\'. ' +
+                   'It must be a valid UUID alias (e.g. 0x1234), ' +
+                   'UUID (lowercase hex characters e.g. ' +
+                   '\'00001234-0000-1000-8000-00805f9b34fb\'), ' +
+                   'or recognized standard name from ' +
+                   'https://developer.bluetooth.org/gatt/services/Pages/ServicesHome.aspx' +
+                   ' e.g. \'alert_notification\'.'
         }, 'Wrong Service name passed.');
     });
 }, 'Wrong Service name. Reject with SyntaxError.');