This commit changes the hover color of links in the footer to keep it
accessible.
The color will be the exact same as the un-hovered version. This is in
line with the other links in the documentation. The links _do_ get
underlined when hovered, so there is still a visual distinction
between the states.
I've added the variable in the `footer` section instead of in `:root`
because the variable I assign it to (`--ifm-footer-link-color`) gets
overridden closer to the footer, so if you set it in `:root`, you end
up with the wrong value.
addresses and closes https://github.com/Unleash/unleash.github.io/issues/8
