Improve lighthouse score for accessibility

[jthoms1]

I'm submitting a ... (check one with "x")
[ ] bug report
[X ] feature request

Currently the lighthouse score for accessibility on the docs site is pretty low. Mostly due to color contrast issues and a few aria label issues.

[dotNetkow]

Was curious and tested this today:
Mobile: 83
Desktop: 76

[averyjohnston]

Confirmed the 83 mentioned above on the latest docs page. Listed issues are:

• Image elements do not have [alt] attributes
• Links do not have a discernible name
• [aria-hidden="true"] elements contain focusable descendents
• Background and foreground colors do not have a sufficient contrast ratio.

This is certainly a lot better than it was when this issue was first posted, but there's still some room for improvement, so I'll go ahead and import this.