src/HOL/Tools/Nitpick/nitpick.ML

       exists is_struct_induct_step (Proof_Context.cases_of ctxt)
     val _ = if standard andalso likely_in_struct_induct_step then
               pprint_nt (fn () => Pretty.blk (0,
                   pstrs "Hint: To check that the induction hypothesis is \
                         \general enough, try this command: " @
-                  [Pretty.mark (Sendback.make_markup {implicit = false, properties = []})
+                  [Pretty.mark
+                    (Active.make_markup Markup.sendbackN {implicit = false, properties = []})
                     (Pretty.blk (0,
                        pstrs ("nitpick [non_std, show_all]")))] @ pstrs "."))
             else
               ()
 (*