Correct WebSocketState.Aborted description (#6967)

Author: chenxinyanc

xml/System.Net.WebSockets/WebSocketState.xml

@@ -68,7 +68,7 @@
       </ReturnValue>
       <MemberValue>6</MemberValue>
       <Docs>
-        <summary>Reserved for future use.</summary>
+        <summary>Indicates that the WebSocket has been aborted.</summary>
       </Docs>
     </Member>
     <Member MemberName="Closed">