Documentation: ABI: document in_temp_input file

For example the BMP280 barometric pressure sensor on Qualcomm
MSM8974-based Nexus 5 smartphone exposes such file in sysfs.
Document it.

Whilst here, fix up incorrect repeated use of X as a wildcard
for in_tempY_input.
Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
Link: https://lore.kernel.org/r/20240406-in_temp_input-v1-1-a1744a4a49e3@z3ntu.xyzSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/ABI/testing/sysfs-bus-iio

@@ -243,7 +243,8 @@ Description:
 		less measurements. Units after application of scale and offset
 		are milli degrees Celsius.
 
-What:		/sys/bus/iio/devices/iio:deviceX/in_tempX_input
+What:		/sys/bus/iio/devices/iio:deviceX/in_tempY_input
+What:		/sys/bus/iio/devices/iio:deviceX/in_temp_input
 KernelVersion:	2.6.38
 Contact:	linux-iio@vger.kernel.org
 Description: