Update docs of wxAppProgressIndicator.

Also mention that MSWGetTaskBarButton is available since 3.1.0.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77640 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/taskbarbutton.h

@@ -351,11 +351,11 @@ public:
         Constructs the wxAppProgressIndicator.
 
         @param parent
-            The parent window handle of wxAppProgressIndicator. Note that the
+            The parent window of wxAppProgressIndicator. Note that the
             window should has taskbar button showing.
         @param maxValue
     */
-    wxAppProgressIndicator(WXWidget parent, int maxValue);
+    wxAppProgressIndicator(wxWindow* parent, int maxValue);
     virtual ~wxAppProgressIndicator();
 
     /**