drm/xe/doc: Include documentation about xe_assert()

Our xe_assert() macros are well documented.
Include that in master documentation.
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://lore.kernel.org/r/20231115112921.1905-1-michal.wajdeczko@intel.comSigned-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Documentation/gpu/xe/index.rst

@@ -22,3 +22,4 @@ DG2, etc is provided to prototype the driver.
    xe_rtp
    xe_firmware
    xe_tile
+   xe_debugging

Documentation/gpu/xe/xe_debugging.rst

+.. SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+
+=========
+Debugging
+=========
+
+.. kernel-doc:: drivers/gpu/drm/xe/xe_assert.h