docs: ABI: convert testing/configfs-acpi to ReST

There are some problems with this file when a ReST content
is produced. Fix it.

Acked-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/f56daf94b80f1051438e8c787ba04552adb66e67.1604042072.git.mchehab+huawei@kernel.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>