Add function-level documentation for static function

Author: NathanJPhillips

src/goto-symex/symex_main.cpp

@@ -229,6 +229,12 @@ void goto_symext::symex_threaded_step(
   }
 }
 
+/// Create a default delegate to retrieve function bodies from a
+/// goto_functionst
+/// \param goto_functions The function map from which to retrieve function
+/// bodies
+/// \return A delegate to retrieve function bodies from the given
+/// goto_functionst
 static goto_symext::get_goto_functiont get_function_from_goto_functions(
   const goto_functionst &goto_functions)
 {