More forward-ported wxPython-bindings related cleanup from 2.9.0 branch, also documented wxPGProperty::GetItemAtY()

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@60817 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/propgrid/property.h

@@ -1580,6 +1580,10 @@ public:
     wxArrayInt GetIndicesForStrings( const wxArrayString& strings,
                                      wxArrayString* unmatched = NULL ) const;
 
+    /** Returns property at given virtual y coordinate.
+    */
+    wxPGProperty* GetItemAtY( unsigned int y ) const;
+
     /**
         Returns @true if item at given index has a valid value;
     */