Footer links `:hover` state

[louismaximepiton]

Context

At some point, we used to have a discrepancy between the hovered rendering of the footer links:

• there were underlined only in the Download page example after an a11y review
• there weren't underlined anywhere else

So we decided to drop the underlined version in #2415 for consistency.

Description

The aim of this issue is to study whether we need to update our hovered footer links guidelines or not:

or