Fixed API doc

Terminal.Gui/Views/TextField.cs

@@ -1103,8 +1103,8 @@ public class TextField : View
     }
 
     /// <summary>Virtual method that invoke the <see cref="TextChanging"/> event if it's defined.</summary>
-    /// <param name="newText">The new text to be replaced.</param>
-    /// <returns>The event arguments.</returns>
+    /// <param name="args">The event arguments..</param>
+    /// <returns><see langword="true"/> if the event was cancelled.</returns>
     public bool OnTextChanging (CancelEventArgs<string> args)
     {
         TextChanging?.Invoke (this, args);