Update ClientCapabilities type

Author: Kapil Borle

src/PowerShellEditorServices.Protocol/LanguageServer/ClientCapabilities.cs

@@ -18,6 +18,9 @@ namespace Microsoft.PowerShell.EditorServices.Protocol.LanguageServer
     /// </summary>
     public class ClientCapabilities
     {
+        public WorkspaceClientCapabilities Workspace { get; set; }
+        public TextDocumentClientCapabilities TextDocument { get; set; }
+        public object Experimental { get; set; }
     }
 }