Fixed a typo in the spec.

--HG--
extra : convert_revision : svn%3Afdd8eb12-d10e-0410-9acb-85c331704f74/trunk%404135

dlib/gui_widgets/fonts_abstract.h

@@ -477,7 +477,7 @@ namespace dlib
 
 // ----------------------------------------------------------------------------------------
 
-    const font* get_native_font (
+    const shared_ptr_thread_safe<font> get_native_font(
     );
     /*!
         ensures