Add documentation for WebSocketProtocol class and its members. (#3553)

* Add documentation for WebSocketProtocol class and its members.

* Apply suggestions from code review

Co-Authored-By: Tom Dykstra <[email protected]>

Author: jozkee

xml/System.Net.WebSockets/WebSocketProtocol.xml

@@ -16,7 +16,7 @@
   </Base>
   <Interfaces />
   <Docs>
-    <summary>To be added.</summary>
+    <summary>The WebSocket class allows applications to send and receive data after the WebSocket upgrade has completed.</summary>
     <remarks>To be added.</remarks>
   </Docs>
   <Members>
@@ -43,12 +43,12 @@
         <Parameter Name="keepAliveInterval" Type="System.TimeSpan" />
       </Parameters>
       <Docs>
-        <param name="stream">To be added.</param>
-        <param name="isServer">To be added.</param>
-        <param name="subProtocol">To be added.</param>
-        <param name="keepAliveInterval">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="stream">The stream for the connection.</param>
+        <param name="isServer"><see langword="true" /> to indicate it's the server-side of the connection; <see langword="false" /> if it's the client-side.</param>
+        <param name="subProtocol">The agreed upon sub-protocol that was used when creating the connection.</param>
+        <param name="keepAliveInterval">The keep-alive interval to use, or <see cref="F:System.Threading.Timeout.InfiniteTimeSpan" /> to disable keep-alives.</param>
+        <summary>Creates a new WebSocket connection that operates on the specified stream.</summary>
+        <returns>The new WebSocket connection.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>