Implement wxComboCtrl::GetSizeFromTextSize().

Improve calculation of wxComboCtrl best size which doesn't work correctly for
non-default fonts as shown by r72935. It is still not perfect but better now.

Closes #14825.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@72955 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/generic/combog.cpp

@@ -259,7 +259,7 @@ void wxGenericComboCtrl::OnPaintEvent( wxPaintEvent& WXUNUSED(event) )
         wxPen pen1( wxColour(133,133,133),
                     customBorder,
                     wxSOLID );
-#else        
+#else
         wxPen pen1( wxSystemSettings::GetColour(wxSYS_COLOUR_GRAYTEXT),
                     customBorder,
                     wxPENSTYLE_SOLID);