Kevin,
I used to update this documentation manually, and then I updated the Kernel documentation about 4 years ago now from the VA's VDL when they released the HTML documentation. But I just checked, and it's on the VDL anymore, which probably means they don't maintain it anymore.
My day job has nothing to do directly with VistA, so I have no motivation today to update it anymore. However, if anybody wants, they can go through the Kernel developer manual, find the new APIs, and make pages for them.
--Sam