fix(Makefile): generate nav_data for appendices
fix(Makefile): generate nav_data for appendices

close leanprover/lean#745

leanprover/tutorial,avigad/tutorial,cjmazey/fork_leanprover_tutorial,soonhokong/lean-tutorial,fpvandoorn/tutorial,Hodapp87/cs6460_project,cjmazey/fork_leanprover_tutorial,soonhokong/lean-tutorial,cjmazey/fork_leanprover_tutorial,avigad/tutorial,Hodapp87/cs6460_project,Hodapp87/cs6460_project,leanprover/tutorial,soonhokong/lean-tutorial,avigad/tutorial,leanprover/tutorial,fpvandoorn/tutorial,fpvandoorn/tutorial