Document wxDV_NO_HEADER style.

Closes #11559.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@62943 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/dataview.h

@@ -596,6 +596,8 @@ public:
     @style{wxDV_VARIABLE_LINE_HEIGHT}
            Allow variable line heights.
            This can be inefficient when displaying large number of items.
+    @style{wxDV_NO_HEADER}
+           Do not show column headers (which are shown by default).
     @endStyleTable
 
     @beginEventEmissionTable{wxDataViewEvent}