Be more explicit about bins too narrow for float representation

If the computed range for the binning divided by the number of bins is lower than the minimum float difference at the scale, we receive an error `[ValueError: Bins not in rising order.]` which is not very informative.

To reproduce:

```
data = [1, np.nextafter(1, 2)]
physt.h1(data)
```

It also happens when the range is 0, like in:

```
data = [1, 1]
physt.h1(data)
```