This commit mostly just adds the framework required to scrape
documentation out of the ISL sources and headers. The method chosen
here is a combination of doxygen and breathe (a sphinx extension for
doxygen integration). I'll freely admit that doxygen is pretty terrible
but it seems like the best option we have available to us today.
Acked-by: Emma Anholt <emma@anholt.net>
Acked-by: Daniel Stone <daniels@collabora.com>
Acked-by: Erik Faye-Lund <erik.faye-lund@collabora.com>.
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11366>