cherry picking documentation patches to 8.1 branch

[Eli Zaretskii]

> From: Szabolcs Nagy <szabolcs.nagy@arm.com>
> Date: Wed, 9 May 2018 17:00:55 +0100
> NoDisclaimer: True
> 
> hello, i'd like to backport these patches into the 8.1 branch:

Thanks, this is obviously fine with me.