bug#33093: 26.1, 7.2 emacs-mac; M-x list-colors-display RET; L1 is black on black

[Juri Linkov]

>> Sorry, this was implemented intentionally: the first column shows
>> the combination of different background colors with the user's
>> foreground color.  You can see its usefulness after changing the default
>> foreground color for example with 'M-x set-foreground-color RET blue RET'.
>
> I believe that hides the problem lower down to blue foreground on blue 
> background.
>
> Doing 'M-x set-foreground-color RET blue RET’ lets L1 be somewhat legible; 
> but L22, L23 are not at all.

When a sample text is not legible this warns the user against using such
combination of foreground and background colors in user's configuration,
i.e. it's easier for users to visually skip such hardly legible text
in the list when choosing a suitable color.