docs: make osgeo_utils.samples a clickable link

[pjonsson]

Feature description

The second paragraph on the page https://gdal.org/en/latest/api/python_samples.html mentions a osgeo_utils.samples sub-module. It would be helpful if that was a clickable link.

Additional context

I clicked on the "Python Sample Scripts" in the API documentation, and was expecting to find references to the source code for Python sample scripts.