Fix typo for MinimizeWindowCommand property on Windows Desktop 6 (#8003)

Author: skylarnam

xml/System.Windows/SystemCommands.xml

@@ -196,8 +196,8 @@
         <ReturnType>System.Windows.Input.RoutedCommand</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>Gets a command that maximizes a window.</summary>
-        <value>A command that maximizes a window.</value>
+        <summary>Gets a command that minimizes a window.</summary>
+        <value>A command that minimizes a window.</value>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>