Nouveau: Border color for count on a selected nav is too light

[r-a-y]

See attached screenshot:

In the image, "Notifications" is selected, but the count looks like it is white-on-white.

Here's what it looks like after the attached patch:

Side note: I think we might need to audit our colo(u)rs for contrast accessibility. I'm noticing a lot of light-gray that is hard to view.

[DJPaul]

Sure, better is better for now.

[hnla]

Side note: I think we might need to audit our colo(u)rs for contrast accessibility

@mercime did do a significant amount of contrast checking a while back to ensure light greys fell within contrast params.

[r-a-y]

In 12068:

Nouveau: Make border color darker for the selected nav item count.

Fixes #7804.

[mercime]

@hugo @r-a-y Contrast checking for WCAG 2.0 AA compliance only involves the colors of text and background combination. Done.

There are failing link color issues coming from themes which I addressed in #7222 for BP Legacy for the respective default Twenty-* themes. Haven't done that in BP Nouveau because we have no stylesheets for respective themes, unless you want to hijack all themes' default link colors, whoa!