cherry picking documentation patches to 8.1 branch

[Joel Brobecker]

> > hello, i'd like to backport these patches into the 8.1 branch:
> 
> Thanks, this is obviously fine with me.

Excellent. But before you do the push, please make sure to have
a GDB/PR number, describing what the issues are, and with the target
milestone set to 8.1.1. Once you have that, if you could please add
that reference to the ChangeLog entries and commits' revision log.

Example of such a PR, which should link you to the attached commits,
and in particular how we put the GDB PR number in the ChangeLog and
revision log:

https://sourceware.org/bugzilla/show_bug.cgi?id=22849

(this is SOP for pushing patches to a release branch once the first
release off that branch has been made).

-- 
Joel