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.xyz


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>