docs/isl: use hawkmoth instead of doxygen

Use the hawkmoth c:auto* directives to incorporate isl documentation.

Convert @param style parameter descriptions to rst info field lists.
Add static stubs for generated headers. Fix a lot of references, in
particular the symbols are now in the Sphinx C domain, not C++
domain. Tweak syntax here and there.

Based on the earlier work by Erik Faye-Lund <kusmabite@gmail.com>

Reviewed-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24507>

docs/header-stubs/intel/dev/intel_wa.h

@@ -0,0 +1,3 @@
+enum intel_workaround_id {
+   INTEL_WA_NUM
+};