docs: iio: Allow creating cross-references ABI

Now that Documentation/ABI is processed by automarkup, let it
generate cross-references for the corresponding ABI file.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/10e7d46360b5e5782d5c09e2706ba47c2315df4f.1739254867.git.mchehab+huawei@kernel.org

Author: mchehab

Documentation/driver-api/iio/core.rst

@@ -60,7 +60,7 @@ directory.  Common attributes are:
 * :file:`sampling_frequency_available`, available discrete set of sampling
   frequency values for device.
 * Available standard attributes for IIO devices are described in the
-  :file:`Documentation/ABI/testing/sysfs-bus-iio` file in the Linux kernel
+  :file:Documentation/ABI/testing/sysfs-bus-iio file in the Linux kernel
   sources.
 
 IIO device channels

Documentation/iio/iio_devbuf.rst

@@ -148,5 +148,5 @@ applied), however there are corner cases in which the buffered data may be found
 in a processed form. Please note that these corner cases are not addressed by
 this documentation.
 
-Please see ``Documentation/ABI/testing/sysfs-bus-iio`` for a complete
+Please see Documentation/ABI/testing/sysfs-bus-iio for a complete
 description of the attributes.