update property to method

Author: jwmsft

windows.ui.xaml/sizehelper_getisempty_1023510010.md

@@ -27,7 +27,7 @@ The [Size](../windows.foundation/size.md) to evaluate.
 
 ## -remarks
 
-Do not use this property to test for zero area; a size with zero area is not necessarily the [Empty](sizehelper_empty.md) size. For more information, see the [Empty](sizehelper_empty.md) property.
+Do not use this method to test for zero area; a size with zero area is not necessarily the [Empty](sizehelper_empty.md) size. For more information, see the [Empty](sizehelper_empty.md) property.
 
 ## -examples