Provide a checkered transparent background for images in the resource listing

[pushfoo]

Enhancement request:

What should be added/changed?

A checkered background for images in the resource listing.

What would it help with?

Making transparency legible.

1. Go to https://api.arcade.academy/en/latest/resources.html?highlight=resource#id11
2. Look at codepage_437.png
3. Note that the white pixels do not show up on the default theme

How?

We previously added transparency to the arcade.color listing. Perhaps we can re-use the solution from there?