Update Driver Doc Page Validator

[sommersoft]

There is reportedly some issue with adding library RTD pages as a subproject to the core's RTD project. As such, some newer libraries are being added to the drivers.rst page with their direct RTD URL.

Update validate_core_driver_page to also check for the direct RTD URL.

[evaherrada]

Hey, do you have an example of this happening? I'd like to do this, but I looked through drivers.rst and I couldn't find any examples of what I thought you were referring to happening, although I was likely looking for the wrong thing.