Has this 2D filter for enhancing circular dots in images a name?
This is a matched filter, where the shape of the filter coincides with the shape of the signal to be detected.

In this case, whenever the filter convolution overlaps a circular dot in the image, a maximum will be present in the output image. Thus, searching for the single maximum pixels in the output image will give the center position of dots in the original image.

Note that your linked source mentions that it is a matched filter.