I have found different symbols for squat toilets. Here are a few of the ones I have encountered along with a photo of what a squat toilet looks like. They all seem to come with the fancy steps up to the platform. Shanghai doesn’t have too many of this style toilets (thank goodness!), most places have “Western toilets” but you can run into a few. I found more in Beijing than Shanghai and of course the further from large cities they will be available.