I have seen bold and I have seen inverted commas. I haven't seen combinations.
Simply say which you are going to use at the beginning. For example, I just found this in 'Beginning Android Application Development': "Code is presented in two different ways: We use a monofont type with no highlighting for most code examples. We use bolding to emphasize code that is of particular importance in the present context." (I haven't included their formatting.)
I realise that this code rather than which menu item to choose, but I think there are a lot of similarities.