I thought histograms have to contain a range as their bin.
This is not correct. Histograms show how many units fall into one of a finite number of bins, or what probability there is for an observation to fall into one of these bins.
Sometimes you already have a "natural" finite number of bins, as in the dice throwing example here: 11 bins. Then everything is straightforward.
However, sometimes you have too many bins to plot usefully, or even an infinite number of possible distributions, e.g., when the underlying distribution is continuous. Then, to build a histogram, you discretize the observations into a small number of bins, where every bin corresponds to a range of possible observations (where ranges should of course not overlap) - and then you proceed as above.