Use wxNB_MULTILINE in wxPreferencesEditor

The size of the dialog in wxPreferencesEditor's generic implementation
is determined from notebook pages alone and doesn't account for label
size, which may be significantly longer in some languages (German,
Danish). If the labels don't fit into the window, some of the tabs are
hidden behind scroll buttons that are easy to overlook.

Improve usability by using wxNB_MULTILINE, which will use multiple rows
of tabs in this situation. This is what e.g. Internet Explorer does in
its preferences as well.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_3_0_BRANCH@78396 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/generic/preferencesg.cpp

@@ -52,7 +52,7 @@ public:
 
         wxSizer *sizer = new wxBoxSizer(wxVERTICAL);
 
-        m_notebook = new wxNotebook(this, wxID_ANY);
+        m_notebook = new wxNotebook(this, wxID_ANY, wxDefaultPosition, wxDefaultSize, wxNB_MULTILINE);
         sizer->Add(m_notebook, wxSizerFlags(1).Expand().DoubleBorder());
 
 #ifdef __WXGTK__