bug#54794: Clarify licence of guix.gnu.org screenshots

[Tobias Geerinckx-Rice]

On 2022-04-08 18:01, Tobias Geerinckx-Rice via Bug reports for GNU Guix 
wrote:
> or CC0

…was probably a stupid suggestion, as some of these images embed at 
least the CC-BY-SA 4.0 GNU Guix logo.

(One wonders: are screenshots of incompatibly-licenced software 
artworks… illegal?)

Kind regards,

T G-R

Sent from a Web browser.  Excuse or enjoy my brevity.