docs: laptops: convert to ReST

Rename the laptops documentation files to ReST, add an
index for them and adjust in order to produce a nice html
output via the Sphinx build system.

At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>

drivers/platform/x86/Kconfig

@@ -448,7 +448,7 @@ config SONY_LAPTOP
 	  screen brightness control, Fn keys and allows powering on/off some
 	  devices.
 
-	  Read <file:Documentation/laptops/sony-laptop.txt> for more information.
+	  Read <file:Documentation/laptops/sony-laptop.rst> for more information.
 
 config SONYPI_COMPAT
 	bool "Sonypi compatibility"
@@ -500,7 +500,7 @@ config THINKPAD_ACPI
 	  support for Fn-Fx key combinations, Bluetooth control, video
 	  output switching, ThinkLight control, UltraBay eject and more.
 	  For more information about this driver see
-	  <file:Documentation/laptops/thinkpad-acpi.txt> and
+	  <file:Documentation/laptops/thinkpad-acpi.rst> and
 	  <http://ibm-acpi.sf.net/> .
 
 	  This driver was formerly known as ibm-acpi.