Document wxNotificationMessage::Timeout_XXX values.

Closes #14009.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@70650 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/notifmsg.h

@@ -24,6 +24,13 @@
 class wxNotificationMessage : public wxEvtHandler
 {
 public:
+    /// Possible values for Show() timeout.
+    enum
+    {
+        Timeout_Auto = -1,  ///< Notification will be hidden automatically.
+        Timeout_Never = 0   ///< Notification will never time out.
+    };
+
     /**
         Default constructor, use SetParent(), SetTitle() and SetMessage() to
         initialize the object before showing it.