add information on the new Microsoft Test Platform

Author: OsirisTerje

docs/articles/vs-test-adapter/NUnit-And-Microsoft-Test-Platform.md

@@ -20,7 +20,7 @@ To change a current test project to use MTP, you need to use version 5 of the NU
 Note that this version can run both MTP and non-MTP, and you can easily switch between them by setting to project
 properties.
 
-In a propertygroup (use the top level one), add the following two properties
+In a property group (use the top level one), add the following two properties
 
 ```xml
    <EnableNUnitRunner>true</EnableNUnitRunner>