Add a possibility to beep on no match to wxGenericTreeCtrl.

For consistency with Windows, allow to optionally generate a beep when
incremental search in the tree control doesn't find anything.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@72638 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775