ABI: testing: sysfs-class-oxp: add missing documentation

ABI: testing: sysfs-class-oxp: add missing documentation

Add missing documentation about the tt_toggle attribute that was added
in kernel 6.5.

Fixes: be144ee491272 ("hwmon: (oxp-sensors) Add tt_toggle attribute on supported boards")
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Derek J. Clark <derekjohn.clark@gmail.com>
Signed-off-by: Antheas Kapenekakis <lkml@antheas.dev>
Link: https://lore.kernel.org/r/20250425111821.88746-5-lkml@antheas.dev
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>