Manual consistency

[zimoun]

Hi Ludo,

(from: http://issues.guix.gnu.org/issue/41253#10)

On Fri, 5 Jun 2020 at 18:36, Ludovic Courtès <ludo@gnu.org> wrote:

> > There are many examples in guix.texi with $, and also many without. Plus
> > some with # as the command line prompt.
>
> Yeah, the manual is kinda inconsistent, and I’m self-inconsistent to
> tell the truth.  :-)
>
> I’ve come to the conclusion that snippets that contain only input should
> be written without a prompt, for easier copy/pasting.
>
> (I’ve seen Python documentation where JS magic allows people to toggle
> prompt display, I find it nice.)

I propose to do a pass on that:
 - apply this rule: no-$ for only input and $ to distinguish between
inputs and outputs.
 - backtick ` replaced by $(...) as discussed elsewhere
and then send a "Fix typo" patch.  And maybe add a bullet in the
Contributing Section.

WDYT?

All the best,
simon