Merge branch 'im/menu' of https://github.com/imciner2/wxWidgets

Make wxEVT_MENU_HIGHLIGHT generation when there is no highlighted item
consistent across all the major ports: use wxID_NONE instead of wxID_ANY
in wxGTK and send these events, which were previously not sent at all in
this case, in wxOSX.

See https://github.com/wxWidgets/wxWidgets/pull/1637

docs/changes.txt

@@ -83,6 +83,10 @@ Changes in behaviour not resulting in compilation errors
   coordinates, e.g. returned by wxWindow::GetSize() by GetContentScaleFactor()
   before using them with OpenGL functions.
 
+- wxGTK now uses wxID_NONE item ID for wxEVT_MENU_HIGHLIGHT events sent when
+  there is no highlighted menu item, instead of wxID_ANY used before, for
+  consistency with wxMSW.
+
 
 Changes in behaviour which may result in build errors
 -----------------------------------------------------